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UVC 摄像头驱动(二)描述符分析

16-11-17        来源:[db:作者]  
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当一个 usb 设备接入时,usb 主机控制器会与设备交互,读取出设备的所有的描述符,并且调用相应 usb_driver 的 probe 函数,同时传入一个接口的指针,因为一个接口代表一个逻辑上的 usb 设备。如果 usb 设备含有多个接口,同时都被这个 usb_driver 支持的话,probe 函数就会被调用多次。
  对于一个 usb 设备来说,首先它有一个设备描述符,一个设备可能会拥有多个配置,每一个配置都拥有一个配置描述符,配置可以理解成多个接口的组合。那么一个配置会拥有多个接口,每一个接口会拥有一个接口描述符,同时一个接口又会有多个设置,设置可以理解成多个端点的组合,每一个端点拥有一个端点描述符。关于详细的设备、配置、接口、设置、那么对于 usb video class 它在标准的 usb 协议上进行了扩展,扩展的部分称为 class specific ,完整的关系如下图所示:



  在 UVC 1.5 Class specification 的第三章,有专门对 UVC 的描述符进行解释,在第 3.1 节,给出了一个完整uvc设备描述符的布局如下图所示:

这里写图片描述

其中,Device 等白色的描述符为标准描述符,灰色是 class specific 描述符。

 

IAD Interface Association Descriptor

一个设备需要用一个联合接口描述符(IAD)来描述一个视频接口集合,对于每一个设备功能需要一个视频控制接口(VideoControl Interface)和一个或者多个视频流接口(VideoStreaming Interface)。标准的视频接口联合描述符和标准接口联合描述符定义相同。在代码中,它体现在“配置”中。

struct usb_host_config {  
    struct usb_config_descriptor    desc;   // 配置描述符  

    char *string;         
    struct usb_interface_assoc_descriptor *intf_assoc[USB_MAXIADS];//IAD
    struct usb_interface *interface[USB_MAXINTERFACES]; // 接口  
    struct usb_interface_cache *intf_cache[USB_MAXINTERFACES];  
    unsigned char *extra;   
    int extralen;  
};  

那么这个联合接口描述符(IAD)有什么含义呢?



举例:

 

Interface Association:
      bLength                 8
      bDescriptorType        11
      bFirstInterface         0
      bInterfaceCount         2
      bFunctionClass         14 Video
      bFunctionSubClass       3 Video Interface Collection
      bFunctionProtocol       0 
      iFunction        

该接口联合描述符中表明了,它是两个接口的集合,起始接口为 0 ,其实没啥意义。大致可以知道是一个控制接口和一个流接口。

VideoControl Interface Descriptors

 

这里写图片描述

  它包含两部分,一个是白色标准视频控制接口描述符,其余的灰色是UVC类特殊的视频控制接口描述符。

 

Standard VC Interface Descriptor

  标准 VC 接口描述符和标准接口描述符的定义是一样的,定义在 section 9.6.5 “Interface” of USB Specification Revision 2.0 。代码中,它包含在接口的设置里。

struct usb_host_interface {  
    struct usb_interface_descriptor desc;   // 接口描述符  
    struct usb_host_endpoint *endpoint;  
    char *string;       /* iInterface string, if present */  
    unsigned char *extra;   /* Class-Specific VC Interface Descriptor */  
    int extralen;  
};  

 



举例:

 

Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        0
      bAlternateSetting       0
      bNumEndpoints           1
      bInterfaceClass        14 Video
      bInterfaceSubClass      1 Video Control
      bInterfaceProtocol      0 
      iInterface              2 

主要信息:这是第0号接口,是一个 video_control 接口。

Class-Specific VC Interface Descriptor

  UVC 类特殊接口描述符是一连串的描述符,它包含了所有用来描述设备功能的描述符,比如 unit 和 terminal 描述符。它和标准接口描述符为与同一个结构体里。

struct usb_host_interface {  
    struct usb_interface_descriptor desc;   // 接口描述符  
    struct usb_host_endpoint *endpoint;  
    char *string;       /* iInterface string, if present */  
    unsigned char *extra;   /* Class-Specific VC Interface Descriptor */  
    int extralen;  /* lenth of Class-Specific VC Interface Descriptor */  
};  

举例:

VideoControl Interface Descriptor:
        bLength                13
        bDescriptorType        36
        bDescriptorSubtype      1 (HEADER)
        bcdUVC               1.00
        wTotalLength          109
        dwClockFrequency       48.000000MHz
        bInCollection           1
        baInterfaceNr( 0)       1
      VideoControl Interface Descriptor:
        bLength                18
        bDescriptorType        36
        bDescriptorSubtype      2 (INPUT_TERMINAL)
        bTerminalID             1
        wTerminalType      0x0201 Camera Sensor
        bAssocTerminal          0
        iTerminal               0 
        wObjectiveFocalLengthMin      0
        wObjectiveFocalLengthMax      0
        wOcularFocalLength            0
        bControlSize                  3
        bmControls           0x00000006
          Auto-Exposure Mode
          Auto-Exposure Priority
      VideoControl Interface Descriptor:
        bLength                11
        bDescriptorType        36
        bDescriptorSubtype      5 (PROCESSING_UNIT)
      Warning: Descriptor too short
        bUnitID                 2
        bSourceID               1
        wMaxMultiplier      16384
        bControlSize            2
        bmControls     0x0000153f
          Brightness
          Contrast
          Hue
          Saturation
          Sharpness
          Gamma
          Backlight Compensation
          Power Line Frequency
          White Balance Temperature, Auto
        iProcessing             0 
        bmVideoStandards     0x1d
          None
          PAL - 625/50
          SECAM - 625/50
          NTSC - 625/50
      VideoControl Interface Descriptor:
        bLength                29
        bDescriptorType        36
        bDescriptorSubtype      6 (EXTENSION_UNIT)
        bUnitID                 3
        guidExtensionCode         {82066163-7050-ab49-b8cc-b3855e8d221d}
        bNumControl             0
        bNrPins                 1
        baSourceID( 0)          2
        bControlSize            4
        bmControls( 0)       0xff
        bmControls( 1)       0xff
        bmControls( 2)       0x1d
        bmControls( 3)       0x00
        iExtension              0 
      VideoControl Interface Descriptor:
        bLength                29
        bDescriptorType        36
        bDescriptorSubtype      6 (EXTENSION_UNIT)
        bUnitID                 4
        guidExtensionCode         {64e7c624-515f-7e43-9089-28ffa487bdca}
        bNumControl             0
        bNrPins                 1
        baSourceID( 0)          3
        bControlSize            4
        bmControls( 0)       0x0f
        bmControls( 1)       0x00
        bmControls( 2)       0x00
        bmControls( 3)       0x00
        iExtension              0 
      VideoControl Interface Descriptor:
        bLength                 9
        bDescriptorType        36
        bDescriptorSubtype      3 (OUTPUT_TERMINAL)
        bTerminalID             5
        wTerminalType      0x0101 USB Streaming
        bAssocTerminal          0
        bSourceID               4
        iTerminal               0 
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x87  EP 7 IN
        bmAttributes            3
          Transfer Type            Interrupt
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0010  1x 16 bytes
        bInterval               8

  前面在摄像头硬件描述中,我们说在控制接口中抽象出了两个概念,一个是 unit 另一个 terminal ,unit 和 terminal 的信息就包含在这些描述符信息中了。它们直连的链接关系可以通过描述符中的 bSourceID 或者 baSourceID 来分析,比如这款摄像头,它的硬件模型就是:
  IT -> PU ->EU -> EU ->OT 具体的描述符含义,参考 UVC 1.5 Class specification Table 3-3 到 3-10 .

VC Interrupt Endpoint Descriptors

中断端点描述符也分为标准中断端点描述符和UVC类特殊的中断端点描述符

Standard VC Interrupt Endpoint Descriptor Class-specific VC Interrupt Endpoint Descriptor

它们在代码中位于 “端点”中:

struct usb_host_endpoint {  
    struct usb_endpoint_descriptor  desc;   // 端点描述符  
    struct list_head        urb_list;   // 该端点的 urb 队列  
    void                *hcpriv;  
    struct ep_device        *ep_dev;    /* For sysfs info */  
    struct usb_host_ss_ep_comp  *ss_ep_comp;    /* For SS devices */  
    unsigned char *extra;/* Class-specific VC Interrupt Endpoint Descriptor */  
    int extralen;/* lenth of Class-specific VC Interrupt Endpoint Descriptor */  
    int enabled;  
}; 

具体的定义与说明参考:
  UVC 1.5 Class specification Table 3-11
  UVC 1.5 Class specification Table 3-12

VideoStreaming Interface Descriptors

 


这里写图片描述

视频流接口描述符包含了所有用来描述视频流接口特性的相关信息。

 

Standard VS Interface Descriptor

  标准视频流接口描述符和标准接口描述符的定义相同,在section 9.6.5 “Interface” of USB Specification Revision 2.0 or USB Specification Revision 3.0 中定义.



举例:

 

    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        1
      bAlternateSetting       0
      bNumEndpoints           0
      bInterfaceClass        14 Video
      bInterfaceSubClass      2 Video Streaming
      bInterfaceProtocol      0 
      iInterface              0 

主要信息,它是第1号接口,接口类型是 video_streaming

Class-Specific VS Interface Descriptors

  UVC 类特殊视频流接口由 input header 、oupt header 、format 和 frame 描述符组成,每一个视频流接口都有一个单独的 input 或者 output header 描述符,对于它支持的每一个 format 都有一个单独的 format 描述符,对于每一个 format 描述符如果需要的话会包含多个 frame 描述符。format 和 frame 描述符仅仅会定义在接口的第0号设置中。
定义参考:
  Table 3-14 Class-specific VS Interface Input Header Descriptor
  USB_Video_Payload_Uncompressed_1.5
  USB_Video_Payload_MJPEG_1.5
  USB_Video_Payload_Frame_Based_1.5
举例:

VideoStreaming Interface Descriptor:
        bLength                            15
        bDescriptorType                    36
        bDescriptorSubtype                  1 (INPUT_HEADER)
        bNumFormats                         2
        wTotalLength                      525
        bEndPointAddress                  129
        bmInfo                              0
        bTerminalLink                       5
        bStillCaptureMethod                 1
        bTriggerSupport                     1
        bTriggerUsage                       0
        bControlSize                        1
        bmaControls( 0)                    27
        bmaControls( 1)                    27
      VideoStreaming Interface Descriptor:
        bLength                            27
        bDescriptorType                    36
        bDescriptorSubtype                  4 (FORMAT_UNCOMPRESSED)
        bFormatIndex                        1
        bNumFrameDescriptors                7
        guidFormat                            {59555932-0000-1000-8000-00aa00389b71}
        bBitsPerPixel                      16
        bDefaultFrameIndex                  1
        bAspectRatioX                       0
        bAspectRatioY                       0
        bmInterlaceFlags                 0x00
          Interlaced stream or variable: No
          Fields per frame: 2 fields
          Field 1 first: No
          Field pattern: Field 1 only
          bCopyProtect                      0
      VideoStreaming Interface Descriptor:
        bLength                            34
        bDescriptorType                    36
        bDescriptorSubtype                  5 (FRAME_UNCOMPRESSED)
        bFrameIndex                         1
        bmCapabilities                   0x01
          Still image supported
        wWidth                            640
        wHeight                           480
        dwMinBitRate                 73728000
        dwMaxBitRate                147456000
        dwMaxVideoFrameBufferSize      614400
        dwDefaultFrameInterval         333333
        bFrameIntervalType                  2
        dwFrameInterval( 0)            333333
        dwFrameInterval( 1)            666666
      VideoStreaming Interface Descriptor:
        bLength                            34
        bDescriptorType                    36
        bDescriptorSubtype                  5 (FRAME_UNCOMPRESSED)
        bFrameIndex                         2
        bmCapabilities                   0x01
          Still image supported
        wWidth                            160
        wHeight                           120
        dwMinBitRate                  4608000
        dwMaxBitRate                  9216000
        dwMaxVideoFrameBufferSize       38400
        dwDefaultFrameInterval         333333
        bFrameIntervalType                  2
        dwFrameInterval( 0)            333333
        dwFrameInterval( 1)            666666
      VideoStreaming Interface Descriptor:
        bLength                            34
        bDescriptorType                    36
        bDescriptorSubtype                  5 (FRAME_UNCOMPRESSED)
        bFrameIndex                         3
        bmCapabilities                   0x01
          Still image supported
        wWidth                            176
        wHeight                           144
        dwMinBitRate                  6082560
        dwMaxBitRate                 12165120
        dwMaxVideoFrameBufferSize       50688
        dwDefaultFrameInterval         333333
        bFrameIntervalType                  2
        dwFrameInterval( 0)            333333
        dwFrameInterval( 1)            666666
      VideoStreaming Interface Descriptor:
        bLength                            34
        bDescriptorType                    36
        bDescriptorSubtype                  5 (FRAME_UNCOMPRESSED)
        bFrameIndex                         4
        bmCapabilities                   0x01
          Still image supported
        wWidth                            320
        wHeight                           240
        dwMinBitRate                 18432000
        dwMaxBitRate                 36864000
        dwMaxVideoFrameBufferSize      153600
        dwDefaultFrameInterval         333333
        bFrameIntervalType                  2
        dwFrameInterval( 0)            333333
        dwFrameInterval( 1)            666666
      VideoStreaming Interface Descriptor:
        bLength                            34
        bDescriptorType                    36
        bDescriptorSubtype                  5 (FRAME_UNCOMPRESSED)
        bFrameIndex                         5
        bmCapabilities                   0x01
          Still image supported
        wWidth                            352
        wHeight                           288
        dwMinBitRate                 24330240
        dwMaxBitRate                 48660480
        dwMaxVideoFrameBufferSize      202752
        dwDefaultFrameInterval         333333
        bFrameIntervalType                  2
        dwFrameInterval( 0)            333333
        dwFrameInterval( 1)            666666
      VideoStreaming Interface Descriptor:
        bLength                            30
        bDescriptorType                    36
        bDescriptorSubtype                  5 (FRAME_UNCOMPRESSED)
        bFrameIndex                         6
        bmCapabilities                   0x01
          Still image supported
        wWidth                           1280
        wHeight                           720
        dwMinBitRate                147456000
        dwMaxBitRate                147456000
        dwMaxVideoFrameBufferSize     1843200
        dwDefaultFrameInterval        1000000
        bFrameIntervalType                  1
        dwFrameInterval( 0)           1000000
      VideoStreaming Interface Descriptor:
        bLength                            30
        bDescriptorType                    36
        bDescriptorSubtype                  5 (FRAME_UNCOMPRESSED)
        bFrameIndex                         7
        bmCapabilities                   0x01
          Still image supported
        wWidth                           1280
        wHeight                           800
        dwMinBitRate                163840000
        dwMaxBitRate                163840000
        dwMaxVideoFrameBufferSize     2048000
        dwDefaultFrameInterval        1000000
        bFrameIntervalType                  1
        dwFrameInterval( 0)           1000000
      VideoStreaming Interface Descriptor:
        bLength                             6
        bDescriptorType                    36
        bDescriptorSubtype                 13 (COLORFORMAT)
        bColorPrimaries                     1 (BT.709,sRGB)
        bTransferCharacteristics            1 (BT.709)
        bMatrixCoefficients                 4 (SMPTE 170M (BT.601))
      VideoStreaming Interface Descriptor:
        bLength                            11
        bDescriptorType                    36
        bDescriptorSubtype                  6 (FORMAT_MJPEG)
        bFormatIndex                        2
        bNumFrameDescriptors                7
        bFlags                              1
          Fixed-size samples: Yes
        bDefaultFrameIndex                  1
        bAspectRatioX                       0
        bAspectRatioY                       0
        bmInterlaceFlags                 0x00
          Interlaced stream or variable: No
          Fields per frame: 1 fields
          Field 1 first: No
          Field pattern: Field 1 only
          bCopyProtect                      0
      VideoStreaming Interface Descriptor:
        bLength                            34
        bDescriptorType                    36
        bDescriptorSubtype                  7 (FRAME_MJPEG)
        bFrameIndex                         1
        bmCapabilities                   0x01
          Still image supported
        wWidth                            640
        wHeight                           480
        dwMinBitRate                 73728000
        dwMaxBitRate                147456000
        dwMaxVideoFrameBufferSize      614400
        dwDefaultFrameInterval         333333
        bFrameIntervalType                  2
        dwFrameInterval( 0)            333333
        dwFrameInterval( 1)            666666
      VideoStreaming Interface Descriptor:
        bLength                            34
        bDescriptorType                    36
        bDescriptorSubtype                  7 (FRAME_MJPEG)
        bFrameIndex                         2
        bmCapabilities                   0x01
          Still image supported
        wWidth                            160
        wHeight                           120
        dwMinBitRate                  4608000
        dwMaxBitRate                  9216000
        dwMaxVideoFrameBufferSize       38400
        dwDefaultFrameInterval         333333
        bFrameIntervalType                  2
        dwFrameInterval( 0)            333333
        dwFrameInterval( 1)            666666
      VideoStreaming Interface Descriptor:
        bLength                            34
        bDescriptorType                    36
        bDescriptorSubtype                  7 (FRAME_MJPEG)
        bFrameIndex                         3
        bmCapabilities                   0x01
          Still image supported
        wWidth                            176
        wHeight                           144
        dwMinBitRate                  6082560
        dwMaxBitRate                 12165120
        dwMaxVideoFrameBufferSize       50688
        dwDefaultFrameInterval         333333
        bFrameIntervalType                  2
        dwFrameInterval( 0)            333333
        dwFrameInterval( 1)            666666
      VideoStreaming Interface Descriptor:
        bLength                            34
        bDescriptorType                    36
        bDescriptorSubtype                  7 (FRAME_MJPEG)
        bFrameIndex                         4
        bmCapabilities                   0x01
          Still image supported
        wWidth                            320
        wHeight                           240
        dwMinBitRate                 18432000
        dwMaxBitRate                 36864000
        dwMaxVideoFrameBufferSize      153600
        dwDefaultFrameInterval         333333
        bFrameIntervalType                  2
        dwFrameInterval( 0)            333333
        dwFrameInterval( 1)            666666
      VideoStreaming Interface Descriptor:
        bLength                            34
        bDescriptorType                    36
        bDescriptorSubtype                  7 (FRAME_MJPEG)
        bFrameIndex                         5
        bmCapabilities                   0x01
          Still image supported
        wWidth                            352
        wHeight                           288
        dwMinBitRate                 24330240
        dwMaxBitRate                 48660480
        dwMaxVideoFrameBufferSize      202752
        dwDefaultFrameInterval         333333
        bFrameIntervalType                  2
        dwFrameInterval( 0)            333333
        dwFrameInterval( 1)            666666
      VideoStreaming Interface Descriptor:
        bLength                            30
        bDescriptorType                    36
        bDescriptorSubtype                  7 (FRAME_MJPEG)
        bFrameIndex                         6
        bmCapabilities                   0x01
          Still image supported
        wWidth                           1280
        wHeight                           720
        dwMinBitRate                442368000
        dwMaxBitRate                442368000
        dwMaxVideoFrameBufferSize     1843200
        dwDefaultFrameInterval         333333
        bFrameIntervalType                  1
        dwFrameInterval( 0)            333333
      VideoStreaming Interface Descriptor:
        bLength                            30
        bDescriptorType                    36
        bDescriptorSubtype                  7 (FRAME_MJPEG)
        bFrameIndex                         7
        bmCapabilities                   0x01
          Still image supported
        wWidth                           1280
        wHeight                           800
        dwMinBitRate                491520000
        dwMaxBitRate                491520000
        dwMaxVideoFrameBufferSize     2048000
        dwDefaultFrameInterval         333333
        bFrameIntervalType                  1
        dwFrameInterval( 0)            333333
      VideoStreaming Interface Descriptor:
        bLength                             6
        bDescriptorType                    36
        bDescriptorSubtype                 13 (COLORFORMAT)
        bColorPrimaries                     1 (BT.709,sRGB)
        bTransferCharacteristics            1 (BT.709)
        bMatrixCoefficients                 4 (SMPTE 170M (BT.601))

  可以看到,这款摄像头支持两种 format 一种是未压缩的,另一种是压缩的 MJPEG ,对于每一个 format 下面又有多个 frame ,frame 的区别比如像素大小。

VideoStreaming Endpoint Descriptors

  The following sections describe all possible endpoint-related descriptors for the VideoStreaming
interface.

VS Video Data Endpoint Descriptors

Standard VS Isochronous Video Data Endpoint Descriptor

  Table 3-20 Standard VS Isochronous Video Data Endpoint Descriptor

Standard VS Bulk Video Data Endpoint Descriptor

  Table 3-21 Standard VS Bulk Video Data Endpoint Descriptor

VS Bulk Still Image Data Endpoint Descriptors

Standard VS Bulk Still Image Data Endpoint Descriptor

  Table 3-22 Standard VS Bulk Still Image Data Endpoint Descriptor

打印描述符

  根据上述的分析过程,我们可以把所有的描述符信息打印出来,前面举例是lsusb 打印出来的信息,那么,为了方便,我们可以参考 lsusb 的源码来写打印程序。

#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 

#include 

static const char *get_guid(const unsigned char *buf)
{
    static char guid[39];

    /* NOTE:  see RFC 4122 for more information about GUID/UUID
     * structure.  The first fields fields are historically big
     * endian numbers, dating from Apollo mc68000 workstations.
     */
    sprintf(guid, "{%02x%02x%02x%02x"
            "-%02x%02x"
            "-%02x%02x"
            "-%02x%02x"
            "-%02x%02x%02x%02x%02x%02x}",
           buf[0], buf[1], buf[2], buf[3],
           buf[4], buf[5],
           buf[6], buf[7],
           buf[8], buf[9],
           buf[10], buf[11], buf[12], buf[13], buf[14], buf[15]);
    return guid;
}

static void parse_videocontrol_interface(struct usb_interface *intf, unsigned char *buf, int buflen)
{
    static const char * const ctrlnames[] = {
        "Brightness", "Contrast", "Hue", "Saturation", "Sharpness", "Gamma",
        "White Balance Temperature", "White Balance Component", "Backlight Compensation",
        "Gain", "Power Line Frequency", "Hue, Auto", "White Balance Temperature, Auto",
        "White Balance Component, Auto", "Digital Multiplier", "Digital Multiplier Limit",
        "Analog Video Standard", "Analog Video Lock Status"
    };
    static const char * const camctrlnames[] = {
        "Scanning Mode", "Auto-Exposure Mode", "Auto-Exposure Priority",
        "Exposure Time (Absolute)", "Exposure Time (Relative)", "Focus (Absolute)",
        "Focus (Relative)", "Iris (Absolute)", "Iris (Relative)", "Zoom (Absolute)",
        "Zoom (Relative)", "PanTilt (Absolute)", "PanTilt (Relative)",
        "Roll (Absolute)", "Roll (Relative)", "Reserved", "Reserved", "Focus, Auto",
        "Privacy"
    };
    static const char * const stdnames[] = {
        "None", "NTSC - 525/60", "PAL - 625/50", "SECAM - 625/50",
        "NTSC - 625/50", "PAL - 525/60" };
    unsigned int i, ctrls, stds, n, p, termt, freq;

    while (buflen > 0)
    {

        if (buf[1] != USB_DT_CS_INTERFACE)
            printk("      Warning: Invalid descriptor\n");
        else if (buf[0] < 3)
            printk("      Warning: Descriptor too short\n");
        printk("      VideoControl Interface Descriptor:\n"
               "        bLength             %5u\n"
               "        bDescriptorType     %5u\n"
               "        bDescriptorSubtype  %5u ",
               buf[0], buf[1], buf[2]);
        switch (buf[2]) {
        case 0x01:  /* HEADER */
            printk("(HEADER)\n");
            n = buf[11];
            if (buf[0] < 12+n)
                printk("      Warning: Descriptor too short\n");
            freq = buf[7] | (buf[8] << 8) | (buf[9] << 16) | (buf[10] << 24);
            printk("        bcdUVC              %2x.%02x\n"
                   "        wTotalLength        %5u\n"
                   "        dwClockFrequency    %5u.%06uMHz\n"
                   "        bInCollection       %5u\n",
                   buf[4], buf[3], buf[5] | (buf[6] << 8), freq / 1000000,
                   freq % 1000000, n);
            for (i = 0; i < n; i++)
                printk("        baInterfaceNr(%2u)   %5u\n", i, buf[12+i]);
            break;

        case 0x02:  /* INPUT_TERMINAL */
            printk("(INPUT_TERMINAL)\n");
            termt = buf[4] | (buf[5] << 8);
            n = termt == 0x0201 ? 7 : 0;
            if (buf[0] < 8 + n)
                printk("      Warning: Descriptor too short\n");
            printk("        bTerminalID         %5u\n"
                   "        wTerminalType      0x%04x\n"
                   "        bAssocTerminal      %5u\n",
                   buf[3], termt, buf[6]);
            printk("        iTerminal           %5u\n",
                   buf[7]);
            if (termt == 0x0201) {
                n += buf[14];
                printk("        wObjectiveFocalLengthMin  %5u\n"
                       "        wObjectiveFocalLengthMax  %5u\n"
                       "        wOcularFocalLength        %5u\n"
                       "        bControlSize              %5u\n",
                       buf[8] | (buf[9] << 8), buf[10] | (buf[11] << 8),
                       buf[12] | (buf[13] << 8), buf[14]);
                ctrls = 0;
                for (i = 0; i < 3 && i < buf[14]; i++)
                    ctrls = (ctrls << 8) | buf[8+n-i-1];
                printk("        bmControls           0x%08x\n", ctrls);
                for (i = 0; i < 19; i++)
                    if ((ctrls >> i) & 1)
                        printk("          %s\n", camctrlnames[i]);
            }
            break;

        case 0x03:  /* OUTPUT_TERMINAL */
            printk("(OUTPUT_TERMINAL)\n");
            termt = buf[4] | (buf[5] << 8);
            if (buf[0] < 9)
                printk("      Warning: Descriptor too short\n");
            printk("        bTerminalID         %5u\n"
                   "        wTerminalType      0x%04x\n"
                   "        bAssocTerminal      %5u\n"
                   "        bSourceID           %5u\n"
                   "        iTerminal           %5u\n",
                   buf[3], termt, buf[6], buf[7], buf[8]);
            break;

        case 0x04:  /* SELECTOR_UNIT */
            printk("(SELECTOR_UNIT)\n");
            p = buf[4];
            if (buf[0] < 6+p)
                printk("      Warning: Descriptor too short\n");

            printk("        bUnitID             %5u\n"
                   "        bNrInPins           %5u\n",
                   buf[3], p);
            for (i = 0; i < p; i++)
                printk("        baSource(%2u)        %5u\n", i, buf[5+i]);
            printk("        iSelector           %5u\n",
                   buf[5+p]);
            break;

        case 0x05:  /* PROCESSING_UNIT */
            printk("(PROCESSING_UNIT)\n");
            n = buf[7];
            if (buf[0] < 10+n)
                printk("      Warning: Descriptor too short\n");
            printk("        bUnitID             %5u\n"
                   "        bSourceID           %5u\n"
                   "        wMaxMultiplier      %5u\n"
                   "        bControlSize        %5u\n",
                   buf[3], buf[4], buf[5] | (buf[6] << 8), n);
            ctrls = 0;
            for (i = 0; i < 3 && i < n; i++)
                ctrls = (ctrls << 8) | buf[8+n-i-1];
            printk("        bmControls     0x%08x\n", ctrls);
            for (i = 0; i < 18; i++)
                if ((ctrls >> i) & 1)
                    printk("          %s\n", ctrlnames[i]);
            stds = buf[9+n];
            printk("        iProcessing         %5u\n"
                   "        bmVideoStandards     0x%2x\n", buf[8+n], stds);
            for (i = 0; i < 6; i++)
                if ((stds >> i) & 1)
                    printk("          %s\n", stdnames[i]);
            break;

        case 0x06:  /* EXTENSION_UNIT */
            printk("(EXTENSION_UNIT)\n");
            p = buf[21];
            n = buf[22+p];
            if (buf[0] < 24+p+n)
                printk("      Warning: Descriptor too short\n");
            printk("        bUnitID             %5u\n"
                   "        guidExtensionCode         %s\n"
                   "        bNumControl         %5u\n"
                   "        bNrPins             %5u\n",
                   buf[3], get_guid(&buf[4]), buf[20], buf[21]);
            for (i = 0; i < p; i++)
                printk("        baSourceID(%2u)      %5u\n", i, buf[22+i]);
            printk("        bControlSize        %5u\n", buf[22+p]);
            for (i = 0; i < n; i++)
                printk("        bmControls(%2u)       0x%02x\n", i, buf[23+p+i]);
            printk("        iExtension          %5u\n",
                   buf[23+p+n]);
            break;

        default:
            printk("(unknown)\n"
                   "        Invalid desc subtype:");
            break;
        }

        buflen -= buf[0];
        buf    += buf[0];
    }
}


static void parse_videostreaming_interface(struct usb_interface *intf, unsigned char *buf, int buflen)
{
    static const char * const colorPrims[] = { "Unspecified", "BT.709,sRGB",
        "BT.470-2 (M)", "BT.470-2 (B,G)", "SMPTE 170M", "SMPTE 240M" };
    static const char * const transferChars[] = { "Unspecified", "BT.709",
        "BT.470-2 (M)", "BT.470-2 (B,G)", "SMPTE 170M", "SMPTE 240M",
        "Linear", "sRGB"};
    static const char * const matrixCoeffs[] = { "Unspecified", "BT.709",
        "FCC", "BT.470-2 (B,G)", "SMPTE 170M (BT.601)", "SMPTE 240M" };
    unsigned int i, m, n, p, flags, len;

    while (buflen > 0)
    {

        if (buf[1] != USB_DT_CS_INTERFACE)
            printk("      Warning: Invalid descriptor\n");
        else if (buf[0] < 3)
            printk("      Warning: Descriptor too short\n");
        printk("      VideoStreaming Interface Descriptor:\n"
               "        bLength                         %5u\n"
               "        bDescriptorType                 %5u\n"
               "        bDescriptorSubtype              %5u ",
               buf[0], buf[1], buf[2]);
        switch (buf[2]) {
        case 0x01: /* INPUT_HEADER */
            printk("(INPUT_HEADER)\n");
            p = buf[3];
            n = buf[12];
            if (buf[0] < 13+p*n)
                printk("      Warning: Descriptor too short\n");
            printk("        bNumFormats                     %5u\n"
                   "        wTotalLength                    %5u\n"
                   "        bEndPointAddress                %5u\n"
                   "        bmInfo                          %5u\n"
                   "        bTerminalLink                   %5u\n"
                   "        bStillCaptureMethod             %5u\n"
                   "        bTriggerSupport                 %5u\n"
                   "        bTriggerUsage                   %5u\n"
                   "        bControlSize                    %5u\n",
                   p, buf[4] | (buf[5] << 8), buf[6], buf[7], buf[8],
                   buf[9], buf[10], buf[11], n);
            for (i = 0; i < p; i++)
                printk(
                "        bmaControls(%2u)                 %5u\n",
                    i, buf[13+p*n]);
            break;

        case 0x02: /* OUTPUT_HEADER */
            printk("(OUTPUT_HEADER)\n");
            p = buf[3];
            n = buf[8];
            if (buf[0] < 9+p*n)
                printk("      Warning: Descriptor too short\n");
            printk("        bNumFormats                 %5u\n"
                   "        wTotalLength                %5u\n"
                   "        bEndpointAddress            %5u\n"
                   "        bTerminalLink               %5u\n"
                   "        bControlSize                %5u\n",
                   p, buf[4] | (buf[5] << 8), buf[6], buf[7], n);
            for (i = 0; i < p; i++)
                printk(
                "        bmaControls(%2u)             %5u\n",
                    i, buf[9+p*n]);
            break;

        case 0x03: /* STILL_IMAGE_FRAME */
            printk("(STILL_IMAGE_FRAME)\n");
            n = buf[4];
            m = buf[5+4*n];
            if (buf[0] < 6+4*n+m)
                printk("      Warning: Descriptor too short\n");
            printk("        bEndpointAddress                %5u\n"
                   "        bNumImageSizePatterns             %3u\n",
                   buf[3], n);
            for (i = 0; i < n; i++)
                printk("        wWidth(%2u)                      %5u\n"
                       "        wHeight(%2u)                     %5u\n",
                       i, buf[5+4*i] | (buf[6+4*i] << 8),
                       i, buf[7+4*i] | (buf[8+4*i] << 8));
            printk("        bNumCompressionPatterns           %3u\n", n);
            for (i = 0; i < m; i++)
                printk("        bCompression(%2u)                %5u\n",
                       i, buf[6+4*n+i]);
            break;

        case 0x04: /* FORMAT_UNCOMPRESSED */
        case 0x10: /* FORMAT_FRAME_BASED */
            if (buf[2] == 0x04) {
                printk("(FORMAT_UNCOMPRESSED)\n");
                len = 27;
            } else {
                printk("(FORMAT_FRAME_BASED)\n");
                len = 28;
            }
            if (buf[0] < len)
                printk("      Warning: Descriptor too short\n");
            flags = buf[25];
            printk("        bFormatIndex                    %5u\n"
                   "        bNumFrameDescriptors            %5u\n"
                   "        guidFormat                            %s\n"
                   "        bBitsPerPixel                   %5u\n"
                   "        bDefaultFrameIndex              %5u\n"
                   "        bAspectRatioX                   %5u\n"
                   "        bAspectRatioY                   %5u\n"
                   "        bmInterlaceFlags                 0x%02x\n",
                   buf[3], buf[4], get_guid(&buf[5]), buf[21], buf[22],
                   buf[23], buf[24], flags);
            printk("          Interlaced stream or variable: %s\n",
                   (flags & (1 << 0)) ? "Yes" : "No");
            printk("          Fields per frame: %u fields\n",
                   (flags & (1 << 1)) ? 1 : 2);
            printk("          Field 1 first: %s\n",
                   (flags & (1 << 2)) ? "Yes" : "No");
            printk("          Field pattern: ");
            switch ((flags >> 4) & 0x03) {
            case 0:
                printk("Field 1 only\n");
                break;
            case 1:
                printk("Field 2 only\n");
                break;
            case 2:
                printk("Regular pattern of fields 1 and 2\n");
                break;
            case 3:
                printk("Random pattern of fields 1 and 2\n");
                break;
            }
            printk("          bCopyProtect                  %5u\n", buf[26]);
            if (buf[2] == 0x10)
                printk("          bVariableSize                 %5u\n", buf[27]);
            break;

        case 0x05: /* FRAME UNCOMPRESSED */
        case 0x07: /* FRAME_MJPEG */
        case 0x11: /* FRAME_FRAME_BASED */
            if (buf[2] == 0x05) {
                printk("(FRAME_UNCOMPRESSED)\n");
                n = 25;
            } else if (buf[2] == 0x07) {
                printk("(FRAME_MJPEG)\n");
                n = 25;
            } else {
                printk("(FRAME_FRAME_BASED)\n");
                n = 21;
            }
            len = (buf[n] != 0) ? (26+buf[n]*4) : 38;
            if (buf[0] < len)
                printk("      Warning: Descriptor too short\n");
            flags = buf[4];
            printk("        bFrameIndex                     %5u\n"
                   "        bmCapabilities                   0x%02x\n",
                   buf[3], flags);
            printk("          Still image %ssupported\n",
                   (flags & (1 << 0)) ? "" : "un");
            if (flags & (1 << 1))
                printk("          Fixed frame-rate\n");
            printk("        wWidth                          %5u\n"
                   "        wHeight                         %5u\n"
                   "        dwMinBitRate                %9u\n"
                   "        dwMaxBitRate                %9u\n",
                   buf[5] | (buf[6] <<  8), buf[7] | (buf[8] << 8),
                   buf[9] | (buf[10] << 8) | (buf[11] << 16) | (buf[12] << 24),
                   buf[13] | (buf[14] << 8) | (buf[15] << 16) | (buf[16] << 24));
            if (buf[2] == 0x11)
                printk("        dwDefaultFrameInterval      %9u\n"
                       "        bFrameIntervalType              %5u\n"
                       "        dwBytesPerLine              %9u\n",
                       buf[17] | (buf[18] << 8) | (buf[19] << 16) | (buf[20] << 24),
                       buf[21],
                       buf[22] | (buf[23] << 8) | (buf[24] << 16) | (buf[25] << 24));
            else
                printk("        dwMaxVideoFrameBufferSize   %9u\n"
                       "        dwDefaultFrameInterval      %9u\n"
                       "        bFrameIntervalType              %5u\n",
                       buf[17] | (buf[18] << 8) | (buf[19] << 16) | (buf[20] << 24),
                       buf[21] | (buf[22] << 8) | (buf[23] << 16) | (buf[24] << 24),
                       buf[25]);
            if (buf[n] == 0)
                printk("        dwMinFrameInterval          %9u\n"
                       "        dwMaxFrameInterval          %9u\n"
                       "        dwFrameIntervalStep         %9u\n",
                       buf[26] | (buf[27] << 8) | (buf[28] << 16) | (buf[29] << 24),
                       buf[30] | (buf[31] << 8) | (buf[32] << 16) | (buf[33] << 24),
                       buf[34] | (buf[35] << 8) | (buf[36] << 16) | (buf[37] << 24));
            else
                for (i = 0; i < buf[n]; i++)
                    printk("        dwFrameInterval(%2u)         %9u\n",
                           i, buf[26+4*i] | (buf[27+4*i] << 8) |
                           (buf[28+4*i] << 16) | (buf[29+4*i] << 24));
            break;

        case 0x06: /* FORMAT_MJPEG */
            printk("(FORMAT_MJPEG)\n");
            if (buf[0] < 11)
                printk("      Warning: Descriptor too short\n");
            flags = buf[5];
            printk("        bFormatIndex                    %5u\n"
                   "        bNumFrameDescriptors            %5u\n"
                   "        bFlags                          %5u\n",
                   buf[3], buf[4], flags);
            printk("          Fixed-size samples: %s\n",
                   (flags & (1 << 0)) ? "Yes" : "No");
            flags = buf[9];
            printk("        bDefaultFrameIndex              %5u\n"
                   "        bAspectRatioX                   %5u\n"
                   "        bAspectRatioY                   %5u\n"
                   "        bmInterlaceFlags                 0x%02x\n",
                   buf[6], buf[7], buf[8], flags);
            printk("          Interlaced stream or variable: %s\n",
                   (flags & (1 << 0)) ? "Yes" : "No");
            printk("          Fields per frame: %u fields\n",
                   (flags & (1 << 1)) ? 2 : 1);
            printk("          Field 1 first: %s\n",
                   (flags & (1 << 2)) ? "Yes" : "No");
            printk("          Field pattern: ");
            switch ((flags >> 4) & 0x03) {
            case 0:
                printk("Field 1 only\n");
                break;
            case 1:
                printk("Field 2 only\n");
                break;
            case 2:
                printk("Regular pattern of fields 1 and 2\n");
                break;
            case 3:
                printk("Random pattern of fields 1 and 2\n");
                break;
            }
            printk("          bCopyProtect                  %5u\n", buf[10]);
            break;

        case 0x0a: /* FORMAT_MPEG2TS */
            printk("(FORMAT_MPEG2TS)\n");
            len = buf[0] < 23 ? 7 : 23;
            if (buf[0] < len)
                printk("      Warning: Descriptor too short\n");
            printk("        bFormatIndex                    %5u\n"
                   "        bDataOffset                     %5u\n"
                   "        bPacketLength                   %5u\n"
                   "        bStrideLength                   %5u\n",
                   buf[3], buf[4], buf[5], buf[6]);
            if (len > 7)
                printk("        guidStrideFormat                      %s\n",
                       get_guid(&buf[7]));
            break;

        case 0x0d: /* COLORFORMAT */
            printk("(COLORFORMAT)\n");
            if (buf[0] < 6)
                printk("      Warning: Descriptor too short\n");
            printk("        bColorPrimaries                 %5u (%s)\n",
                   buf[3], (buf[3] <= 5) ? colorPrims[buf[3]] : "Unknown");
            printk("        bTransferCharacteristics        %5u (%s)\n",
                   buf[4], (buf[4] <= 7) ? transferChars[buf[4]] : "Unknown");
            printk("        bMatrixCoefficients             %5u (%s)\n",
                   buf[5], (buf[5] <= 5) ? matrixCoeffs[buf[5]] : "Unknown");
            break;

        default:
            printk("        Invalid desc subtype:");
            break;
        }
        buflen -= buf[0];
        buf    += buf[0];
    }
}


static void dump_endpoint(const struct usb_endpoint_descriptor *endpoint)
{
    static const char * const typeattr[] = {
        "Control",
        "Isochronous",
        "Bulk",
        "Interrupt"
    };
    static const char * const syncattr[] = {
        "None",
        "Asynchronous",
        "Adaptive",
        "Synchronous"
    };
    static const char * const usage[] = {
        "Data",
        "Feedback",
        "Implicit feedback Data",
        "(reserved)"
    };
    static const char * const hb[] = { "1x", "2x", "3x", "(?\?)" };
    unsigned wmax = le16_to_cpu(endpoint->wMaxPacketSize);

    printk("      Standard Endpoint Descriptor:\n"
           "        bLength             %5u\n"
           "        bDescriptorType     %5u\n"
           "        bEndpointAddress     0x%02x  EP %u %s\n"
           "        bmAttributes        %5u\n"
           "          Transfer Type            %s\n"
           "          Synch Type               %s\n"
           "          Usage Type               %s\n"
           "        wMaxPacketSize     0x%04x  %s %d bytes\n"
           "        bInterval           %5u\n",
           endpoint->bLength,
           endpoint->bDescriptorType,
           endpoint->bEndpointAddress,
           endpoint->bEndpointAddress & 0x0f,
           (endpoint->bEndpointAddress & 0x80) ? "IN" : "OUT",
           endpoint->bmAttributes,
           typeattr[endpoint->bmAttributes & 3],
           syncattr[(endpoint->bmAttributes >> 2) & 3],
           usage[(endpoint->bmAttributes >> 4) & 3],
           wmax, hb[(wmax >> 11) & 3], wmax & 0x7ff,
           endpoint->bInterval);
    /* only for audio endpoints */
    if (endpoint->bLength == 9)
        printk("        bRefresh            %5u\n"
               "        bSynchAddress       %5u\n",
               endpoint->bRefresh, endpoint->bSynchAddress);

}


static int myuvc_probe(struct usb_interface *intf,
             const struct usb_device_id *id)
{
    static int cnt = 0;
    struct usb_device *dev = interface_to_usbdev(intf);
    struct usb_device_descriptor *descriptor = &dev->descriptor;
    struct usb_host_config *hostconfig;
    struct usb_config_descriptor *config;
    struct usb_interface_assoc_descriptor *assoc_desc;
    struct usb_interface_descriptor *interface;
    struct usb_endpoint_descriptor  *endpoint;
    int i, j, k, l, m;
    unsigned char *buffer;
    int buflen;
    int desc_len;
    int desc_cnt;

    printk("myuvc_probe : cnt = %d\n", cnt++);

    /* 打印设备描述符 */
    printk("Device Descriptor:\n"
           "  bLength             %5u\n"
           "  bDescriptorType     %5u\n"
           "  bcdUSB              %2x.%02x\n"
           "  bDeviceClass        %5u \n"
           "  bDeviceSubClass     %5u \n"
           "  bDeviceProtocol     %5u \n"
           "  bMaxPacketSize0     %5u\n"
           "  idVendor           0x%04x \n"
           "  idProduct          0x%04x \n"
           "  bcdDevice           %2x.%02x\n"
           "  iManufacturer       %5u\n"
           "  iProduct            %5u\n"
           "  iSerial             %5u\n"
           "  bNumConfigurations  %5u\n",
           descriptor->bLength, descriptor->bDescriptorType,
           descriptor->bcdUSB >> 8, descriptor->bcdUSB & 0xff,
           descriptor->bDeviceClass, 
           descriptor->bDeviceSubClass,
           descriptor->bDeviceProtocol, 
           descriptor->bMaxPacketSize0,
           descriptor->idVendor,  descriptor->idProduct,
           descriptor->bcdDevice >> 8, descriptor->bcdDevice & 0xff,
           descriptor->iManufacturer, 
           descriptor->iProduct, 
           descriptor->iSerialNumber, 
           descriptor->bNumConfigurations);

    for (i = 0; i < descriptor->bNumConfigurations; i++)
    {
        hostconfig = &dev->config[i];
        config     = &hostconfig->desc;
        // 配置描述符
        printk("  Configuration Descriptor %d:\n"
               "    bLength             %5u\n"
               "    bDescriptorType     %5u\n"
               "    wTotalLength        %5u\n"
               "    bNumInterfaces      %5u\n"
               "    bConfigurationValue %5u\n"
               "    iConfiguration      %5u\n"
               "    bmAttributes         0x%02x\n",
               i, 
               config->bLength, config->bDescriptorType,
               le16_to_cpu(config->wTotalLength),
               config->bNumInterfaces, config->bConfigurationValue,
               config->iConfiguration,
               config->bmAttributes);
        // 接口联合描述符
        assoc_desc = hostconfig->intf_assoc[0];
        printk("    Interface Association Descriptor:\n"
               "      bLength             %5u\n"
               "      bDescriptorType     %5u\n"
               "      bFirstInterface     %5u\n"
               "      bInterfaceCount     %5u\n"
               "      bFunctionClass      %5u\n"
               "      bFunctionSubClass   %5u\n"
               "      bFunctionProtocol   %5u\n"
               "      iFunction           %5u\n",
            assoc_desc->bLength,
            assoc_desc->bDescriptorType,
            assoc_desc->bFirstInterface,
            assoc_desc->bInterfaceCount,
            assoc_desc->bFunctionClass,
            assoc_desc->bFunctionSubClass,
            assoc_desc->bFunctionProtocol,
            assoc_desc->iFunction);    

            // 打印当前 probe 传进来接口的每一个设置的接口描述符
            for (j = 0; j < intf->num_altsetting; j++)
            {
                interface = &intf->altsetting[j].desc;
                // Standard Interface Descriptor
                printk("    Standard Interface Descriptor -> altsetting %d:\n"
                       "      bLength             %5u\n"
                       "      bDescriptorType     %5u\n"
                       "      bInterfaceNumber    %5u\n"
                       "      bAlternateSetting   %5u\n"
                       "      bNumEndpoints       %5u\n"
                       "      bInterfaceClass     %5u\n"
                       "      bInterfaceSubClass  %5u\n"
                       "      bInterfaceProtocol  %5u\n"
                       "      iInterface          %5u\n",
                       j, 
                       interface->bLength, interface->bDescriptorType, interface->bInterfaceNumber,
                       interface->bAlternateSetting, interface->bNumEndpoints, interface->bInterfaceClass,
                       interface->bInterfaceSubClass, interface->bInterfaceProtocol,
                       interface->iInterface);

                /* 打印端点描述符 */
                for (m = 0; m < interface->bNumEndpoints; m++)
                {
                    endpoint = &intf->altsetting[j].endpoint[m].desc;
                    dump_endpoint(endpoint);

                    /* class specific endpoint Descriptor */
                    buffer = &intf->altsetting[j].endpoint[m].extra;
                    buflen = intf->altsetting[j].endpoint[m].enabled;
                    printk("      Class-specific Endpoint Descriptor:\n");
                    k = 0;
                    desc_cnt = 0;
                    while (k < buflen)
                    {
                        desc_len = buffer[k];
                        printk("extra desc %d: ", desc_cnt);
                        for (l = 0; l < desc_len; l++, k++)
                        {
                            printk("%02x ", buffer[k]);
                        }
                        desc_cnt++;
                        printk("\n");
                    }
                }
            } 
            // 只打印当前设置的 class specific Descriptor
            buffer = intf->cur_altsetting->extra;
            // Class-specific Interface Descriptor
            printk("    Class-specific Interface Descriptor\n");
            buflen = intf->cur_altsetting->extralen;
            printk("extra buffer of interface %d:\n", cnt-1);
            k = 0;
            desc_cnt = 0;
            while (k < buflen)
            {
                desc_len = buffer[k];
                printk("extra desc %d: ", desc_cnt);
                for (l = 0; l < desc_len; l++, k++)
                {
                    printk("%02x ", buffer[k]);
                }
                desc_cnt++;
                printk("\n");
            }
            // 解析 Class-specific Interface Descriptor 
            interface = &intf->cur_altsetting->desc;
            if ((buffer[1] == USB_DT_CS_INTERFACE) && (interface->bInterfaceSubClass == 1))
            {
                parse_videocontrol_interface(intf, buffer, buflen);
            }
            if ((buffer[1] == USB_DT_CS_INTERFACE) && (interface->bInterfaceSubClass == 2))
            {
                parse_videostreaming_interface(intf, buffer, buflen);
            }           
    }    
    return 0;
}

static void myuvc_disconnect(struct usb_interface *intf)
{
    static int cnt = 0;
    printk("myuvc_disconnect : cnt = %d\n", cnt++);
}

static struct usb_device_id myuvc_ids[] = {
    /* Generic USB Video Class */
    { USB_INTERFACE_INFO(USB_CLASS_VIDEO, 1, 0) },  /* VideoControl Interface */
    { USB_INTERFACE_INFO(USB_CLASS_VIDEO, 2, 0) },  /* VideoStreaming Interface */
    {}
};

/* 1. 分配usb_driver */
/* 2. 设置 */
static struct usb_driver myuvc_driver = {
    .name       = "myuvc",
    .probe      = myuvc_probe,
    .disconnect = myuvc_disconnect,
    .id_table   = myuvc_ids,
};

static int myuvc_init(void)
{
    /* 3. 注册 */
    usb_register(&myuvc_driver);
    return 0;
}

static void myuvc_exit(void)
{
    usb_deregister(&myuvc_driver);
}

module_init(myuvc_init);
module_exit(myuvc_exit);
MODULE_LICENSE("GPL");

描述符打印信息

 myuvc_probe : cnt = 0
 Device Descriptor:
   bLength                18
   bDescriptorType         1
   bcdUSB               2.00
   bDeviceClass          239 
   bDeviceSubClass         2 
   bDeviceProtocol         1 
   bMaxPacketSize0        64
   idVendor           0x04f2 
   idProduct          0xb26a 
   bcdDevice           52.68
   iManufacturer           1
   iProduct                2
   iSerial                 0
   bNumConfigurations      1
   Configuration Descriptor 0:
     bLength                 9
     bDescriptorType         2
     wTotalLength          857
     bNumInterfaces          2
     bConfigurationValue     1
     iConfiguration          0
     bmAttributes         0x80
     Interface Association Descriptor:
       bLength                 8
       bDescriptorType        11
       bFirstInterface         0
       bInterfaceCount         2
       bFunctionClass         14
       bFunctionSubClass       3
       bFunctionProtocol       0
       iFunction               2
     Standard Interface Descriptor -> altsetting 0:
       bLength                 9
       bDescriptorType         4
       bInterfaceNumber        0
       bAlternateSetting       0
       bNumEndpoints           1
       bInterfaceClass        14
       bInterfaceSubClass      1
       bInterfaceProtocol      0
       iInterface              2
       Standard Endpoint Descriptor:
         bLength                 7
         bDescriptorType         5
         bEndpointAddress     0x87  EP 7 IN
         bmAttributes            3
           Transfer Type            Interrupt
           Synch Type               None
           Usage Type               Data
         wMaxPacketSize     0x0010  1x 16 bytes
         bInterval               8
    Class-specific Endpoint Descriptor:
        extra desc 0: 05 25 03 10 00 
    Class-specific Interface Descriptor
        extra buffer of interface 0:
        extra desc 0: 0d 24 01 00 01 6d 00 00 6c dc 02 01 01 
        extra desc 1: 12 24 02 01 01 02 00 00 00 00 00 00 00 00 03 06 00 00 
        extra desc 2: 0b 24 05 02 01 00 40 02 3f 15 00 
        extra desc 3: 1d 24 06 03 82 06 61 63 70 50 ab 49 b8 cc b3 85 5e 8d 22 1d 00 01 02 04 ff ff 1d 00 00 
        extra desc 4: 1d 24 06 04 64 e7 c6 24 51 5f 7e 43 90 89 28 ff a4 87 bd ca 00 01 03 04 0f 00 00 00 00 
        extra desc 5: 09 24 03 05 01 01 00 04 00 
       VideoControl Interface Descriptor:
         bLength                13
         bDescriptorType        36
         bDescriptorSubtype      1 (HEADER)
         bcdUVC               1.00
         wTotalLength          109
         dwClockFrequency       48.000000MHz
         bInCollection           1
         baInterfaceNr( 0)       1
       VideoControl Interface Descriptor:
         bLength                18
         bDescriptorType        36
         bDescriptorSubtype      2 (INPUT_TERMINAL)
         bTerminalID             1
         wTerminalType      0x0201
         bAssocTerminal          0
         iTerminal               0
         wObjectiveFocalLengthMin      0
         wObjectiveFocalLengthMax      0
         wOcularFocalLength            0
         bControlSize                  3
         bmControls           0x00000006
           Auto-Exposure Mode
           Auto-Exposure Priority
       VideoControl Interface Descriptor:
         bLength                11
         bDescriptorType        36
         bDescriptorSubtype      5 (PROCESSING_UNIT)
       Warning: Descriptor too short
         bUnitID                 2
         bSourceID               1
         wMaxMultiplier      16384
         bControlSize            2
         bmControls     0x0000153f
           Brightness
           Contrast
           Hue
           Saturation
           Sharpness
           Gamma
           Backlight Compensation
           Power Line Frequency
           White Balance Temperature, Auto
         iProcessing             0
         bmVideoStandards     0x1d
           None
           PAL - 625/50
           SECAM - 625/50
           NTSC - 625/50
       VideoControl Interface Descriptor:
         bLength                29
         bDescriptorType        36
         bDescriptorSubtype      6 (EXTENSION_UNIT)
         bUnitID                 3
         guidExtensionCode         {82066163-7050-ab49-b8cc-b3855e8d221d}
         bNumControl             0
         bNrPins                 1
         baSourceID( 0)          2
         bControlSize            4
         bmControls( 0)       0xff
         bmControls( 1)       0xff
         bmControls( 2)       0x1d
         bmControls( 3)       0x00
         iExtension              0
       VideoControl Interface Descriptor:
         bLength                29
         bDescriptorType        36
         bDescriptorSubtype      6 (EXTENSION_UNIT)
         bUnitID                 4
         guidExtensionCode         {64e7c624-515f-7e43-9089-28ffa487bdca}
         bNumControl             0
         bNrPins                 1
         baSourceID( 0)          3
         bControlSize            4
         bmControls( 0)       0x0f
         bmControls( 1)       0x00
         bmControls( 2)       0x00
         bmControls( 3)       0x00
         iExtension              0
       VideoControl Interface Descriptor:
         bLength                 9
         bDescriptorType        36
         bDescriptorSubtype      3 (OUTPUT_TERMINAL)
         bTerminalID             5
         wTerminalType      0x0101
         bAssocTerminal          0
         bSourceID               4
         iTerminal               0
 myuvc_probe : cnt = 1
 Device Descriptor:
   bLength                18
   bDescriptorType         1
   bcdUSB               2.00
   bDeviceClass          239 
   bDeviceSubClass         2 
   bDeviceProtocol         1 
   bMaxPacketSize0        64
   idVendor           0x04f2 
   idProduct          0xb26a 
   bcdDevice           52.68
   iManufacturer           1
   iProduct                2
   iSerial                 0
   bNumConfigurations      1
   Configuration Descriptor 0:
     bLength                 9
     bDescriptorType         2
     wTotalLength          857
     bNumInterfaces          2
     bConfigurationValue     1
     iConfiguration          0
     bmAttributes         0x80
     Interface Association Descriptor:
       bLength                 8
       bDescriptorType        11
       bFirstInterface         0
       bInterfaceCount         2
       bFunctionClass         14
       bFunctionSubClass       3
       bFunctionProtocol       0
       iFunction               2
     Standard Interface Descriptor -> altsetting 0:
       bLength                 9
       bDescriptorType         4
       bInterfaceNumber        1
       bAlternateSetting       0
       bNumEndpoints           0
       bInterfaceClass        14
       bInterfaceSubClass      2
       bInterfaceProtocol      0
       iInterface              0
     Standard Interface Descriptor -> altsetting 1:
       bLength                 9
       bDescriptorType         4
       bInterfaceNumber        1
       bAlternateSetting       1
       bNumEndpoints           1
       bInterfaceClass        14
       bInterfaceSubClass      2
       bInterfaceProtocol      0
       iInterface              0
       Standard Endpoint Descriptor:
         bLength                 7
         bDescriptorType         5
         bEndpointAddress     0x81  EP 1 IN
         bmAttributes            5
           Transfer Type            Isochronous
           Synch Type               Asynchronous
           Usage Type               Data
         wMaxPacketSize     0x00c0  1x 192 bytes
         bInterval               1
       Class-specific Endpoint Descriptor:
     Standard Interface Descriptor -> altsetting 2:
       bLength                 9
       bDescriptorType         4
       bInterfaceNumber        1
       bAlternateSetting       2
       bNumEndpoints           1
       bInterfaceClass        14
       bInterfaceSubClass      2
       bInterfaceProtocol      0
       iInterface              0
       Standard Endpoint Descriptor:
         bLength                 7
         bDescriptorType         5
         bEndpointAddress     0x81  EP 1 IN
         bmAttributes            5
           Transfer Type            Isochronous
           Synch Type               Asynchronous
           Usage Type               Data
         wMaxPacketSize     0x0180  1x 384 bytes
         bInterval               1
       Class-specific Endpoint Descriptor:
     Standard Interface Descriptor -> altsetting 3:
       bLength                 9
       bDescriptorType         4
       bInterfaceNumber        1
       bAlternateSetting       3
       bNumEndpoints           1
       bInterfaceClass        14
       bInterfaceSubClass      2
       bInterfaceProtocol      0
       iInterface              0
       Standard Endpoint Descriptor:
         bLength                 7
         bDescriptorType         5
         bEndpointAddress     0x81  EP 1 IN
         bmAttributes            5
           Transfer Type            Isochronous
           Synch Type               Asynchronous
           Usage Type               Data
         wMaxPacketSize     0x0200  1x 512 bytes
         bInterval               1
       Class-specific Endpoint Descriptor:
     Standard Interface Descriptor -> altsetting 4:
       bLength                 9
       bDescriptorType         4
       bInterfaceNumber        1
       bAlternateSetting       4
       bNumEndpoints           1
       bInterfaceClass        14
       bInterfaceSubClass      2
       bInterfaceProtocol      0
       iInterface              0
       Standard Endpoint Descriptor:
         bLength                 7
         bDescriptorType         5
         bEndpointAddress     0x81  EP 1 IN
         bmAttributes            5
           Transfer Type            Isochronous
           Synch Type               Asynchronous
           Usage Type               Data
         wMaxPacketSize     0x0280  1x 640 bytes
         bInterval               1
       Class-specific Endpoint Descriptor:
     Standard Interface Descriptor -> altsetting 5:
       bLength                 9
       bDescriptorType         4
       bInterfaceNumber        1
       bAlternateSetting       5
       bNumEndpoints           1
       bInterfaceClass        14
       bInterfaceSubClass      2
       bInterfaceProtocol      0
       iInterface              0
       Standard Endpoint Descriptor:
         bLength                 7
         bDescriptorType         5
         bEndpointAddress     0x81  EP 1 IN
         bmAttributes            5
           Transfer Type            Isochronous
           Synch Type               Asynchronous
           Usage Type               Data
         wMaxPacketSize     0x0320  1x 800 bytes
         bInterval               1
       Class-specific Endpoint Descriptor:
     Standard Interface Descriptor -> altsetting 6:
       bLength                 9
       bDescriptorType         4
       bInterfaceNumber        1
       bAlternateSetting       6
       bNumEndpoints           1
       bInterfaceClass        14
       bInterfaceSubClass      2
       bInterfaceProtocol      0
       iInterface              0
       Standard Endpoint Descriptor:
         bLength                 7
         bDescriptorType         5
         bEndpointAddress     0x81  EP 1 IN
         bmAttributes            5
           Transfer Type            Isochronous
           Synch Type               Asynchronous
           Usage Type               Data
         wMaxPacketSize     0x03b0  1x 944 bytes
         bInterval               1
       Class-specific Endpoint Descriptor:
     Standard Interface Descriptor -> altsetting 7:
       bLength                 9
       bDescriptorType         4
       bInterfaceNumber        1
       bAlternateSetting       7
       bNumEndpoints           1
       bInterfaceClass        14
       bInterfaceSubClass      2
       bInterfaceProtocol      0
       iInterface              0
       Standard Endpoint Descriptor:
         bLength                 7
         bDescriptorType         5
         bEndpointAddress     0x81  EP 1 IN
         bmAttributes            5
           Transfer Type            Isochronous
           Synch Type               Asynchronous
           Usage Type               Data
         wMaxPacketSize     0x0a80  2x 640 bytes
         bInterval               1
       Class-specific Endpoint Descriptor:
     Standard Interface Descriptor -> altsetting 8:
       bLength                 9
       bDescriptorType         4
       bInterfaceNumber        1
       bAlternateSetting       8
       bNumEndpoints           1
       bInterfaceClass        14
       bInterfaceSubClass      2
       bInterfaceProtocol      0
       iInterface              0
       Standard Endpoint Descriptor:
         bLength                 7
         bDescriptorType         5
         bEndpointAddress     0x81  EP 1 IN
         bmAttributes            5
           Transfer Type            Isochronous
           Synch Type               Asynchronous
           Usage Type               Data
         wMaxPacketSize     0x0b20  2x 800 bytes
         bInterval               1
       Class-specific Endpoint Descriptor:
     Standard Interface Descriptor -> altsetting 9:
       bLength                 9
       bDescriptorType         4
       bInterfaceNumber        1
       bAlternateSetting       9
       bNumEndpoints           1
       bInterfaceClass        14
       bInterfaceSubClass      2
       bInterfaceProtocol      0
       iInterface              0
       Standard Endpoint Descriptor:
         bLength                 7
         bDescriptorType         5
         bEndpointAddress     0x81  EP 1 IN
         bmAttributes            5
           Transfer Type            Isochronous
           Synch Type               Asynchronous
           Usage Type               Data
         wMaxPacketSize     0x0be0  2x 992 bytes
         bInterval               1
       Class-specific Endpoint Descriptor:
     Standard Interface Descriptor -> altsetting 10:
       bLength                 9
       bDescriptorType         4
       bInterfaceNumber        1
       bAlternateSetting      10
       bNumEndpoints           1
       bInterfaceClass        14
       bInterfaceSubClass      2
       bInterfaceProtocol      0
       iInterface              0
       Standard Endpoint Descriptor:
         bLength                 7
         bDescriptorType         5
         bEndpointAddress     0x81  EP 1 IN
         bmAttributes            5
           Transfer Type            Isochronous
           Synch Type               Asynchronous
           Usage Type               Data
         wMaxPacketSize     0x1380  3x 896 bytes
         bInterval               1
       Class-specific Endpoint Descriptor:
     Standard Interface Descriptor -> altsetting 11:
       bLength                 9
       bDescriptorType         4
       bInterfaceNumber        1
       bAlternateSetting      11
       bNumEndpoints           1
       bInterfaceClass        14
       bInterfaceSubClass      2
       bInterfaceProtocol      0
       iInterface              0
       Standard Endpoint Descriptor:
         bLength                 7
         bDescriptorType         5
         bEndpointAddress     0x81  EP 1 IN
         bmAttributes            5
           Transfer Type            Isochronous
           Synch Type               Asynchronous
           Usage Type               Data
         wMaxPacketSize     0x13fc  3x 1020 bytes
         bInterval               1
    Class-specific Endpoint Descriptor:
    Class-specific Interface Descriptor
        extra buffer of interface 1:
        extra desc 0: 0f 24 01 02 0d 02 81 00 05 01 01 00 01 00 04 
        extra desc 1: 1b 24 04 01 07 59 55 59 32 00 00 10 00 80 00 00 aa 00 38 9b 71 10 01 00 00 00 00 
        extra desc 2: 22 24 05 01 01 80 02 e0 01 00 00 65 04 00 00 ca 08 00 60 09 00 15 16 05 00 02 15 16 05 00 2a 2c 0a 00 
        extra desc 3: 22 24 05 02 01 a0 00 78 00 00 50 46 00 00 a0 8c 00 00 96 00 00 15 16 05 00 02 15 16 05 00 2a 2c 0a 00 
        extra desc 4: 22 24 05 03 01 b0 00 90 00 00 d0 5c 00 00 a0 b9 00 00 c6 00 00 15 16 05 00 02 15 16 05 00 2a 2c 0a 00 
        extra desc 5: 22 24 05 04 01 40 01 f0 00 00 40 19 01 00 80 32 02 00 58 02 00 15 16 05 00 02 15 16 05 00 2a 2c 0a 00 
        extra desc 6: 22 24 05 05 01 60 01 20 01 00 40 73 01 00 80 e6 02 00 18 03 00 15 16 05 00 02 15 16 05 00 2a 2c 0a 00 
        extra desc 7: 1e 24 05 06 01 00 05 d0 02 00 00 ca 08 00 00 ca 08 00 20 1c 00 40 42 0f 00 01 40 42 0f 00 
        extra desc 8: 1e 24 05 07 01 00 05 20 03 00 00 c4 09 00 00 c4 09 00 40 1f 00 40 42 0f 00 01 40 42 0f 00 
        extra desc 9: 06 24 0d 01 01 04 
        extra desc 10: 0b 24 06 02 07 01 01 00 00 00 00 
        extra desc 11: 22 24 07 01 01 80 02 e0 01 00 00 65 04 00 00 ca 08 00 60 09 00 15 16 05 00 02 15 16 05 00 2a 2c 0a 00 
        extra desc 12: 22 24 07 02 01 a0 00 78 00 00 50 46 00 00 a0 8c 00 00 96 00 00 15 16 05 00 02 15 16 05 00 2a 2c 0a 00 
        extra desc 13: 22 24 07 03 01 b0 00 90 00 00 d0 5c 00 00 a0 b9 00 00 c6 00 00 15 16 05 00 02 15 16 05 00 2a 2c 0a 00 
        extra desc 14: 22 24 07 04 01 40 01 f0 00 00 40 19 01 00 80 32 02 00 58 02 00 15 16 05 00 02 15 16 05 00 2a 2c 0a 00 
        extra desc 15: 22 24 07 05 01 60 01 20 01 00 40 73 01 00 80 e6 02 00 18 03 00 15 16 05 00 02 15 16 05 00 2a 2c 0a 00 
        extra desc 16: 1e 24 07 06 01 00 05 d0 02 00 00 5e 1a 00 00 5e 1a 00 20 1c 00 15 16 05 00 01 15 16 05 00 
        extra desc 17: 1e 24 07 07 01 00 05 20 03 00 00 4c 1d 00 00 4c 1d 00 40 1f 00 15 16 05 00 01 15 16 05 00 
        extra desc 18: 06 24 0d 01 01 04 
       VideoStreaming Interface Descriptor:
         bLength                            15
         bDescriptorType                    36
         bDescriptorSubtype                  1 (INPUT_HEADER)
         bNumFormats                         2
         wTotalLength                      525
         bEndPointAddress                  129
         bmInfo                              0
         bTerminalLink                       5
         bStillCaptureMethod                 1
         bTriggerSupport                     1
         bTriggerUsage                       0
         bControlSize                        1
         bmaControls( 0)                    27
         bmaControls( 1)                    27
       VideoStreaming Interface Descriptor:
         bLength                            27
         bDescriptorType                    36
         bDescriptorSubtype                  4 (FORMAT_UNCOMPRESSED)
         bFormatIndex                        1
         bNumFrameDescriptors                7
         guidFormat                            {59555932-0000-1000-8000-00aa00389b71}
         bBitsPerPixel                      16
         bDefaultFrameIndex                  1
         bAspectRatioX                       0
         bAspectRatioY                       0
         bmInterlaceFlags                 0x00
           Interlaced stream or variable: No
           Fields per frame: 2 fields
           Field 1 first: No
           Field pattern: Field 1 only
           bCopyProtect                      0
       VideoStreaming Interface Descriptor:
         bLength                            34
         bDescriptorType                    36
         bDescriptorSubtype                  5 (FRAME_UNCOMPRESSED)
         bFrameIndex                         1
         bmCapabilities                   0x01
           Still image supported
         wWidth                            640
         wHeight                           480
         dwMinBitRate                 73728000
         dwMaxBitRate                147456000
         dwMaxVideoFrameBufferSize      614400
         dwDefaultFrameInterval         333333
         bFrameIntervalType                  2
         dwFrameInterval( 0)            333333
         dwFrameInterval( 1)            666666
       VideoStreaming Interface Descriptor:
         bLength                            34
         bDescriptorType                    36
         bDescriptorSubtype                  5 (FRAME_UNCOMPRESSED)
         bFrameIndex                         2
         bmCapabilities                   0x01
           Still image supported
         wWidth                            160
         wHeight                           120
         dwMinBitRate                  4608000
         dwMaxBitRate                  9216000
         dwMaxVideoFrameBufferSize       38400
         dwDefaultFrameInterval         333333
         bFrameIntervalType                  2
         dwFrameInterval( 0)            333333
         dwFrameInterval( 1)            666666
       VideoStreaming Interface Descriptor:
         bLength                            34
         bDescriptorType                    36
         bDescriptorSubtype                  5 (FRAME_UNCOMPRESSED)
         bFrameIndex                         3
         bmCapabilities                   0x01
           Still image supported
         wWidth                            176
         wHeight                           144
         dwMinBitRate                  6082560
         dwMaxBitRate                 12165120
         dwMaxVideoFrameBufferSize       50688
         dwDefaultFrameInterval         333333
         bFrameIntervalType                  2
         dwFrameInterval( 0)            333333
         dwFrameInterval( 1)            666666
       VideoStreaming Interface Descriptor:
         bLength                            34
         bDescriptorType                    36
         bDescriptorSubtype                  5 (FRAME_UNCOMPRESSED)
         bFrameIndex                         4
         bmCapabilities                   0x01
           Still image supported
         wWidth                            320
         wHeight                           240
         dwMinBitRate                 18432000
         dwMaxBitRate                 36864000
         dwMaxVideoFrameBufferSize      153600
         dwDefaultFrameInterval         333333
         bFrameIntervalType                  2
         dwFrameInterval( 0)            333333
         dwFrameInterval( 1)            666666
       VideoStreaming Interface Descriptor:
         bLength                            34
         bDescriptorType                    36
         bDescriptorSubtype                  5 (FRAME_UNCOMPRESSED)
         bFrameIndex                         5
         bmCapabilities                   0x01
           Still image supported
         wWidth                            352
         wHeight                           288
         dwMinBitRate                 24330240
         dwMaxBitRate                 48660480
         dwMaxVideoFrameBufferSize      202752
         dwDefaultFrameInterval         333333
         bFrameIntervalType                  2
         dwFrameInterval( 0)            333333
         dwFrameInterval( 1)            666666
       VideoStreaming Interface Descriptor:
         bLength                            30
         bDescriptorType                    36
         bDescriptorSubtype                  5 (FRAME_UNCOMPRESSED)
         bFrameIndex                         6
         bmCapabilities                   0x01
           Still image supported
         wWidth                           1280
         wHeight                           720
         dwMinBitRate                147456000
         dwMaxBitRate                147456000
         dwMaxVideoFrameBufferSize     1843200
         dwDefaultFrameInterval        1000000
         bFrameIntervalType                  1
         dwFrameInterval( 0)           1000000
       VideoStreaming Interface Descriptor:
         bLength                            30
         bDescriptorType                    36
         bDescriptorSubtype                  5 (FRAME_UNCOMPRESSED)
         bFrameIndex                         7
         bmCapabilities                   0x01
           Still image supported
         wWidth                           1280
         wHeight                           800
         dwMinBitRate                163840000
         dwMaxBitRate                163840000
         dwMaxVideoFrameBufferSize     2048000
         dwDefaultFrameInterval        1000000
         bFrameIntervalType                  1
         dwFrameInterval( 0)           1000000
       VideoStreaming Interface Descriptor:
         bLength                             6
         bDescriptorType                    36
         bDescriptorSubtype                 13 (COLORFORMAT)
         bColorPrimaries                     1 (BT.709,sRGB)
         bTransferCharacteristics            1 (BT.709)
         bMatrixCoefficients                 4 (SMPTE 170M (BT.601))
       VideoStreaming Interface Descriptor:
         bLength                            11
         bDescriptorType                    36
         bDescriptorSubtype                  6 (FORMAT_MJPEG)
         bFormatIndex                        2
         bNumFrameDescriptors                7
         bFlags                              1
           Fixed-size samples: Yes
         bDefaultFrameIndex                  1
         bAspectRatioX                       0
         bAspectRatioY                       0
         bmInterlaceFlags                 0x00
           Interlaced stream or variable: No
           Fields per frame: 1 fields
           Field 1 first: No
           Field pattern: Field 1 only
           bCopyProtect                      0
       VideoStreaming Interface Descriptor:
         bLength                            34
         bDescriptorType                    36
         bDescriptorSubtype                  7 (FRAME_MJPEG)
         bFrameIndex                         1
         bmCapabilities                   0x01
           Still image supported
         wWidth                            640
         wHeight                           480
         dwMinBitRate                 73728000
         dwMaxBitRate                147456000
         dwMaxVideoFrameBufferSize      614400
         dwDefaultFrameInterval         333333
         bFrameIntervalType                  2
         dwFrameInterval( 0)            333333
         dwFrameInterval( 1)            666666
       VideoStreaming Interface Descriptor:
         bLength                            34
         bDescriptorType                    36
         bDescriptorSubtype                  7 (FRAME_MJPEG)
         bFrameIndex                         2
         bmCapabilities                   0x01
           Still image supported
         wWidth                            160
         wHeight                           120
         dwMinBitRate                  4608000
         dwMaxBitRate                  9216000
         dwMaxVideoFrameBufferSize       38400
         dwDefaultFrameInterval         333333
         bFrameIntervalType                  2
         dwFrameInterval( 0)            333333
         dwFrameInterval( 1)            666666
       VideoStreaming Interface Descriptor:
         bLength                            34
         bDescriptorType                    36
         bDescriptorSubtype                  7 (FRAME_MJPEG)
         bFrameIndex                         3
         bmCapabilities                   0x01
           Still image supported
         wWidth                            176
         wHeight                           144
         dwMinBitRate                  6082560
         dwMaxBitRate                 12165120
         dwMaxVideoFrameBufferSize       50688
         dwDefaultFrameInterval         333333
         bFrameIntervalType                  2
         dwFrameInterval( 0)            333333
         dwFrameInterval( 1)            666666
       VideoStreaming Interface Descriptor:
         bLength                            34
         bDescriptorType                    36
         bDescriptorSubtype                  7 (FRAME_MJPEG)
         bFrameIndex                         4
         bmCapabilities                   0x01
           Still image supported
         wWidth                            320
         wHeight                           240
         dwMinBitRate                 18432000
         dwMaxBitRate                 36864000
         dwMaxVideoFrameBufferSize      153600
         dwDefaultFrameInterval         333333
         bFrameIntervalType                  2
         dwFrameInterval( 0)            333333
         dwFrameInterval( 1)            666666
       VideoStreaming Interface Descriptor:
         bLength                            34
         bDescriptorType                    36
         bDescriptorSubtype                  7 (FRAME_MJPEG)
         bFrameIndex                         5
         bmCapabilities                   0x01
           Still image supported
         wWidth                            352
         wHeight                           288
         dwMinBitRate                 24330240
         dwMaxBitRate                 48660480
         dwMaxVideoFrameBufferSize      202752
         dwDefaultFrameInterval         333333
         bFrameIntervalType                  2
         dwFrameInterval( 0)            333333
         dwFrameInterval( 1)            666666
       VideoStreaming Interface Descriptor:
         bLength                            30
         bDescriptorType                    36
         bDescriptorSubtype                  7 (FRAME_MJPEG)
         bFrameIndex                         6
         bmCapabilities                   0x01
           Still image supported
         wWidth                           1280
         wHeight                           720
         dwMinBitRate                442368000
         dwMaxBitRate                442368000
         dwMaxVideoFrameBufferSize     1843200
         dwDefaultFrameInterval         333333
         bFrameIntervalType                  1
         dwFrameInterval( 0)            333333
       VideoStreaming Interface Descriptor:
         bLength                            30
         bDescriptorType                    36
         bDescriptorSubtype                  7 (FRAME_MJPEG)
         bFrameIndex                         7
         bmCapabilities                   0x01
           Still image supported
         wWidth                           1280
         wHeight                           800
         dwMinBitRate                491520000
         dwMaxBitRate                491520000
         dwMaxVideoFrameBufferSize     2048000
         dwDefaultFrameInterval         333333
         bFrameIntervalType                  1
         dwFrameInterval( 0)            333333
       VideoStreaming Interface Descriptor:
         bLength                             6
         bDescriptorType                    36
         bDescriptorSubtype                 13 (COLORFORMAT)
         bColorPrimaries                     1 (BT.709,sRGB)
         bTransferCharacteristics            1 (BT.709)
         bMatrixCoefficients                 4 (SMPTE 170M (BT.601))
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