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8 UVCs can't work well on RP4B #3606

Open steven-hz opened 4 years ago

steven-hz commented 4 years ago

6 uvc can works fine with 2 powered hubs, but when the num of uvc is 8 , RP4B will report :

USB isochronous frame lost (-18). [2020/05/11 16:17:43][ 575.912821] uvcvideo: USB isochronous frame lost (-18). Then, the v4l2 api can't get the the random 2 video streams through VIDIOC_DQBUF cmd of ioctl.

Follow is th log of lsusb and lsusb -v 

Bus 002 Device 002: ID 2109:0813 VIA Labs, Inc. 
Bus 002 Device 003: ID 2109:0817 VIA Labs, Inc. 
Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 001 Device 007: ID 1d6b:0102 Linux Foundation EEM Gadget
Bus 001 Device 006: ID 1d6b:0102 Linux Foundation EEM Gadget
Bus 001 Device 005: ID 1d6b:0102 Linux Foundation EEM Gadget
Bus 001 Device 004: ID 1d6b:0102 Linux Foundation EEM Gadget
Bus 001 Device 003: ID 2109:2813 VIA Labs, Inc. 
Bus 001 Device 012: ID 1d6b:0102 Linux Foundation EEM Gadget
Bus 001 Device 011: ID 1d6b:0102 Linux Foundation EEM Gadget
Bus 001 Device 010: ID 1d6b:0102 Linux Foundation EEM Gadget
Bus 001 Device 009: ID 1d6b:0102 Linux Foundation EEM Gadget
Bus 001 Device 008: ID 2109:2817 VIA Labs, Inc. 
Bus 001 Device 002: ID 2109:3431 VIA Labs, Inc. Hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
pi@raspberrypi:$ lsusb -v

Bus 002 Device 002: ID 2109:0813 VIA Labs, Inc. 
Couldn't open device, some information will be missing
Device Descriptor:
  bLength                18
  bDescriptorType         1
  bcdUSB               3.00
  bDeviceClass            9 Hub
  bDeviceSubClass         0 
  bDeviceProtocol         3 
  bMaxPacketSize0         9
  idVendor           0x2109 VIA Labs, Inc.
  idProduct          0x0813 
  bcdDevice           90.11
  iManufacturer           1 
  iProduct                2 
  iSerial                 0 
  bNumConfigurations      1
  Configuration Descriptor:
    bLength                 9
    bDescriptorType         2
    wTotalLength       0x001f
    bNumInterfaces          1
    bConfigurationValue     1
    iConfiguration          0 
    bmAttributes         0xe0
      Self Powered
      Remote Wakeup
    MaxPower                0mA
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        0
      bAlternateSetting       0
      bNumEndpoints           1
      bInterfaceClass         9 Hub
      bInterfaceSubClass      0 
      bInterfaceProtocol      0 Full speed (or root) hub
      iInterface              0 
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x81  EP 1 IN
        bmAttributes           19
          Transfer Type            Interrupt
          Synch Type               None
          Usage Type               Feedback
        wMaxPacketSize     0x0002  1x 2 bytes
        bInterval               8
        bMaxBurst               0

Bus 002 Device 003: ID 2109:0817 VIA Labs, Inc. 
Couldn't open device, some information will be missing
Device Descriptor:
  bLength                18
  bDescriptorType         1
  bcdUSB               3.10
  bDeviceClass            9 Hub
  bDeviceSubClass         0 
  bDeviceProtocol         3 
  bMaxPacketSize0         9
  idVendor           0x2109 VIA Labs, Inc.
  idProduct          0x0817 
  bcdDevice            2.14
  iManufacturer           1 
  iProduct                2 
  iSerial                 0 
  bNumConfigurations      1
  Configuration Descriptor:
    bLength                 9
    bDescriptorType         2
    wTotalLength       0x001f
    bNumInterfaces          1
    bConfigurationValue     1
    iConfiguration          0 
    bmAttributes         0xe0
      Self Powered
      Remote Wakeup
    MaxPower                0mA
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        0
      bAlternateSetting       0
      bNumEndpoints           1
      bInterfaceClass         9 Hub
      bInterfaceSubClass      0 
      bInterfaceProtocol      0 Full speed (or root) hub
      iInterface              0 
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x81  EP 1 IN
        bmAttributes           19
          Transfer Type            Interrupt
          Synch Type               None
          Usage Type               Feedback
        wMaxPacketSize     0x0002  1x 2 bytes
        bInterval               8
        bMaxBurst               0

Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Couldn't open device, some information will be missing
Device Descriptor:
  bLength                18
  bDescriptorType         1
  bcdUSB               3.00
  bDeviceClass            9 Hub
  bDeviceSubClass         0 
  bDeviceProtocol         3 
  bMaxPacketSize0         9
  idVendor           0x1d6b Linux Foundation
  idProduct          0x0003 3.0 root hub
  bcdDevice            4.19
  iManufacturer           3 
  iProduct                2 
  iSerial                 1 
  bNumConfigurations      1
  Configuration Descriptor:
    bLength                 9
    bDescriptorType         2
    wTotalLength       0x001f
    bNumInterfaces          1
    bConfigurationValue     1
    iConfiguration          0 
    bmAttributes         0xe0
      Self Powered
      Remote Wakeup
    MaxPower                0mA
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        0
      bAlternateSetting       0
      bNumEndpoints           1
      bInterfaceClass         9 Hub
      bInterfaceSubClass      0 
      bInterfaceProtocol      0 Full speed (or root) hub
      iInterface              0 
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x81  EP 1 IN
        bmAttributes            3
          Transfer Type            Interrupt
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0004  1x 4 bytes
        bInterval              12
        bMaxBurst               0

Bus 001 Device 007: ID 1d6b:0102 Linux Foundation EEM Gadget
Couldn't open device, some information will be missing
Device Descriptor:
  bLength                18
  bDescriptorType         1
  bcdUSB               2.00
  bDeviceClass          239 Miscellaneous Device
  bDeviceSubClass         2 
  bDeviceProtocol         1 Interface Association
  bMaxPacketSize0        64
  idVendor           0x1d6b Linux Foundation
  idProduct          0x0102 EEM Gadget
  bcdDevice            3.18
  iManufacturer           1 
  iProduct                2 
  iSerial                 0 
  bNumConfigurations      1
  Configuration Descriptor:
    bLength                 9
    bDescriptorType         2
    wTotalLength       0x032a
    bNumInterfaces          2
    bConfigurationValue     1
    iConfiguration          4 
    bmAttributes         0xc0
      Self Powered
    MaxPower                2mA
    Interface Association:
      bLength                 8
      bDescriptorType        11
      bFirstInterface         0
      bInterfaceCount         2
      bFunctionClass         14 Video
      bFunctionSubClass       3 Video Interface Collection
      bFunctionProtocol       0 
      iFunction               5 
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        0
      bAlternateSetting       0
      bNumEndpoints           1
      bInterfaceClass        14 Video
      bInterfaceSubClass      1 Video Control
      bInterfaceProtocol      0 
      iInterface              5 
      VideoControl Interface Descriptor:
        bLength                13
        bDescriptorType        36
        bDescriptorSubtype      1 (HEADER)
        bcdUVC               1.00
        wTotalLength       0x0033
        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           0x00000002
          Auto-Exposure Mode
      VideoControl Interface Descriptor:
        bLength                11
        bDescriptorType        36
        bDescriptorSubtype      5 (PROCESSING_UNIT)
      Warning: Descriptor too short
        bUnitID                 2
        bSourceID               1
        wMaxMultiplier      16384
        bControlSize            2
        bmControls     0x0000177f
          Brightness
          Contrast
          Hue
          Saturation
          Sharpness
          Gamma
          White Balance Temperature
          Backlight Compensation
          Gain
          Power Line Frequency
          White Balance Temperature, Auto
        iProcessing             0 
        bmVideoStandards     0x09
          None
          SECAM - 625/50
      VideoControl Interface Descriptor:
        bLength                 9
        bDescriptorType        36
        bDescriptorSubtype      3 (OUTPUT_TERMINAL)
        bTerminalID             3
        wTerminalType      0x0101 USB Streaming
        bAssocTerminal          0
        bSourceID               2
        iTerminal               0 
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x83  EP 3 IN
        bmAttributes            3
          Transfer Type            Interrupt
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0010  1x 16 bytes
        bInterval               8
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        1
      bAlternateSetting       0
      bNumEndpoints           0
      bInterfaceClass        14 Video
      bInterfaceSubClass      2 Video Streaming
      bInterfaceProtocol      0 
      iInterface              6 
      VideoStreaming Interface Descriptor:
        bLength                            16
        bDescriptorType                    36
        bDescriptorSubtype                  1 (INPUT_HEADER)
        bNumFormats                         3
        wTotalLength                   0x0268
        bEndPointAddress                  135
        bmInfo                              0
        bTerminalLink                       3
        bStillCaptureMethod                 0
        bTriggerSupport                     0
        bTriggerUsage                       0
        bControlSize                        1
        bmaControls( 0)                     0
        bmaControls( 1)                     0
        bmaControls( 2)                     0
      VideoStreaming Interface Descriptor:
        bLength                            11
        bDescriptorType                    36
        bDescriptorSubtype                  6 (FORMAT_MJPEG)
        bFormatIndex                        1
        bNumFrameDescriptors                5
        bFlags                              0
          Fixed-size samples: No
        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                            50
        bDescriptorType                    36
        bDescriptorSubtype                  7 (FRAME_MJPEG)
        bFrameIndex                         1
        bmCapabilities                   0x00
          Still image unsupported
        wWidth                           1920
        wHeight                          1080
        dwMinBitRate                331776000
        dwMaxBitRate                995328000
        dwMaxVideoFrameBufferSize     4147200
        dwDefaultFrameInterval         333333
        bFrameIntervalType                  6
        dwFrameInterval( 0)            333333
        dwFrameInterval( 1)            400000
        dwFrameInterval( 2)            500000
        dwFrameInterval( 3)            666666
        dwFrameInterval( 4)           1000000
        dwFrameInterval( 5)           2000000
      VideoStreaming Interface Descriptor:
        bLength                            50
        bDescriptorType                    36
        bDescriptorSubtype                  7 (FRAME_MJPEG)
        bFrameIndex                         2
        bmCapabilities                   0x00
          Still image unsupported
        wWidth                           1280
        wHeight                           720
        dwMinBitRate                147456000
        dwMaxBitRate                442368000
        dwMaxVideoFrameBufferSize     1843200
        dwDefaultFrameInterval         333333
        bFrameIntervalType                  6
        dwFrameInterval( 0)            333333
        dwFrameInterval( 1)            400000
        dwFrameInterval( 2)            500000
        dwFrameInterval( 3)            666666
        dwFrameInterval( 4)           1000000
        dwFrameInterval( 5)           2000000
      VideoStreaming Interface Descriptor:
        bLength                            50
        bDescriptorType                    36
        bDescriptorSubtype                  7 (FRAME_MJPEG)
        bFrameIndex                         3
        bmCapabilities                   0x00
          Still image unsupported
        wWidth                            640
        wHeight                           480
        dwMinBitRate                 49152000
        dwMaxBitRate                147456000
        dwMaxVideoFrameBufferSize     1843200
        dwDefaultFrameInterval         333333
        bFrameIntervalType                  6
        dwFrameInterval( 0)            333333
        dwFrameInterval( 1)            400000
        dwFrameInterval( 2)            500000
        dwFrameInterval( 3)            666666
        dwFrameInterval( 4)           1000000
        dwFrameInterval( 5)           2000000
      VideoStreaming Interface Descriptor:
        bLength                            50
        bDescriptorType                    36
        bDescriptorSubtype                  7 (FRAME_MJPEG)
        bFrameIndex                         4
        bmCapabilities                   0x00
          Still image unsupported
        wWidth                            352
        wHeight                           288
        dwMinBitRate                 16220160
        dwMaxBitRate                 48660480
        dwMaxVideoFrameBufferSize     4147200
        dwDefaultFrameInterval         333333
        bFrameIntervalType                  6
        dwFrameInterval( 0)            333333
        dwFrameInterval( 1)            400000
        dwFrameInterval( 2)            500000
        dwFrameInterval( 3)            666666
        dwFrameInterval( 4)           1000000
        dwFrameInterval( 5)           2000000
      VideoStreaming Interface Descriptor:
        bLength                            50
        bDescriptorType                    36
        bDescriptorSubtype                  7 (FRAME_MJPEG)
        bFrameIndex                         5
        bmCapabilities                   0x00
          Still image unsupported
        wWidth                           1024
        wHeight                           768
        dwMinBitRate                125829120
        dwMaxBitRate                377487360
        dwMaxVideoFrameBufferSize     4147200
        dwDefaultFrameInterval         333333
        bFrameIntervalType                  6
        dwFrameInterval( 0)            333333
        dwFrameInterval( 1)            400000
        dwFrameInterval( 2)            500000
        dwFrameInterval( 3)            666666
        dwFrameInterval( 4)           1000000
        dwFrameInterval( 5)           2000000
      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                            27
        bDescriptorType                    36
        bDescriptorSubtype                  4 (FORMAT_UNCOMPRESSED)
        bFormatIndex                        2
        bNumFrameDescriptors                2
        guidFormat                            {32595559-0000-0010-8000-00aa00389b71}
        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                            38
        bDescriptorType                    36
        bDescriptorSubtype                  5 (FRAME_UNCOMPRESSED)
        bFrameIndex                         1
        bmCapabilities                   0x00
          Still image unsupported
        wWidth                            640
        wHeight                           480
        dwMinBitRate                 49152000
        dwMaxBitRate                147456000
        dwMaxVideoFrameBufferSize      614400
        dwDefaultFrameInterval         333333
        bFrameIntervalType                  3
        dwFrameInterval( 0)            333333
        dwFrameInterval( 1)            666666
        dwFrameInterval( 2)           1000000
      VideoStreaming Interface Descriptor:
        bLength                            38
        bDescriptorType                    36
        bDescriptorSubtype                  5 (FRAME_UNCOMPRESSED)
        bFrameIndex                         2
        bmCapabilities                   0x00
          Still image unsupported
        wWidth                           1280
        wHeight                           720
        dwMinBitRate                147456000
        dwMaxBitRate                442368000
        dwMaxVideoFrameBufferSize     1843200
        dwDefaultFrameInterval        1000000
        bFrameIntervalType                  3
        dwFrameInterval( 0)            666666
        dwFrameInterval( 1)           1000000
        dwFrameInterval( 2)           2000000
      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                            28
        bDescriptorType                    36
        bDescriptorSubtype                 16 (FORMAT_FRAME_BASED)
        bFormatIndex                        3
        bNumFrameDescriptors                5
        guidFormat                            {34363248-0000-0010-8000-00aa00389b71}
        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
        bVariableSize                     1
      VideoStreaming Interface Descriptor:
        bLength                            38
        bDescriptorType                    36
        bDescriptorSubtype                 17 (FRAME_FRAME_BASED)
        bFrameIndex                         1
        bmCapabilities                   0x00
          Still image unsupported
        wWidth                           1920
        wHeight                          1080
        dwMinBitRate                 29491200
        dwMaxBitRate                 29491200
        dwDefaultFrameInterval         333333
        bFrameIntervalType                  3
        dwBytesPerLine                      0
        dwFrameInterval( 0)            333333
        dwFrameInterval( 1)            666666
        dwFrameInterval( 2)           1000000
      VideoStreaming Interface Descriptor:
        bLength                            38
        bDescriptorType                    36
        bDescriptorSubtype                 17 (FRAME_FRAME_BASED)
        bFrameIndex                         2
        bmCapabilities                   0x00
          Still image unsupported
        wWidth                           1280
        wHeight                           720
        dwMinBitRate                 29491200
        dwMaxBitRate                 29491200
        dwDefaultFrameInterval         333333
        bFrameIntervalType                  3
        dwBytesPerLine                      0
        dwFrameInterval( 0)            333333
        dwFrameInterval( 1)            666666
        dwFrameInterval( 2)           1000000
      VideoStreaming Interface Descriptor:
        bLength                            38
        bDescriptorType                    36
        bDescriptorSubtype                 17 (FRAME_FRAME_BASED)
        bFrameIndex                         3
        bmCapabilities                   0x00
          Still image unsupported
        wWidth                            640
        wHeight                           480
        dwMinBitRate                 29491200
        dwMaxBitRate                 29491200
        dwDefaultFrameInterval         333333
        bFrameIntervalType                  3
        dwBytesPerLine                      0
        dwFrameInterval( 0)            333333
        dwFrameInterval( 1)            666666
        dwFrameInterval( 2)           1000000
      VideoStreaming Interface Descriptor:
        bLength                            38
        bDescriptorType                    36
        bDescriptorSubtype                 17 (FRAME_FRAME_BASED)
        bFrameIndex                         4
        bmCapabilities                   0x00
          Still image unsupported
        wWidth                            352
        wHeight                           288
        dwMinBitRate                 29491200
        dwMaxBitRate                 29491200
        dwDefaultFrameInterval         333333
        bFrameIntervalType                  3
        dwBytesPerLine                      0
        dwFrameInterval( 0)            333333
        dwFrameInterval( 1)            666666
        dwFrameInterval( 2)           1000000
      VideoStreaming Interface Descriptor:
        bLength                            38
        bDescriptorType                    36
        bDescriptorSubtype                 17 (FRAME_FRAME_BASED)
        bFrameIndex                         5
        bmCapabilities                   0x00
          Still image unsupported
        wWidth                           1024
        wHeight                           768
        dwMinBitRate                 29491200
        dwMaxBitRate                 29491200
        dwDefaultFrameInterval         333333
        bFrameIntervalType                  3
        dwBytesPerLine                      0
        dwFrameInterval( 0)            333333
        dwFrameInterval( 1)            666666
        dwFrameInterval( 2)           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))
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        1
      bAlternateSetting       1
      bNumEndpoints           1
      bInterfaceClass        14 Video
      bInterfaceSubClass      2 Video Streaming
      bInterfaceProtocol      0 
      iInterface              6 
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x87  EP 7 IN
        bmAttributes            5
          Transfer Type            Isochronous
          Synch Type               Asynchronous
          Usage Type               Data
        wMaxPacketSize     0x0080  1x 128 bytes
        bInterval               1
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        1
      bAlternateSetting       2
      bNumEndpoints           1
      bInterfaceClass        14 Video
      bInterfaceSubClass      2 Video Streaming
      bInterfaceProtocol      0 
      iInterface              0 
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x87  EP 7 IN
        bmAttributes            5
          Transfer Type            Isochronous
          Synch Type               Asynchronous
          Usage Type               Data
        wMaxPacketSize     0x0100  1x 256 bytes
        bInterval               1
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        1
      bAlternateSetting       3
      bNumEndpoints           1
      bInterfaceClass        14 Video
      bInterfaceSubClass      2 Video Streaming
      bInterfaceProtocol      0 
      iInterface              0 
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x87  EP 7 IN
        bmAttributes            5
          Transfer Type            Isochronous
          Synch Type               Asynchronous
          Usage Type               Data
        wMaxPacketSize     0x0200  1x 512 bytes
        bInterval               1
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        1
      bAlternateSetting       4
      bNumEndpoints           1
      bInterfaceClass        14 Video
      bInterfaceSubClass      2 Video Streaming
      bInterfaceProtocol      0 
      iInterface              0 
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x87  EP 7 IN
        bmAttributes            5
          Transfer Type            Isochronous
          Synch Type               Asynchronous
          Usage Type               Data
        wMaxPacketSize     0x0400  1x 1024 bytes
        bInterval               1
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        1
      bAlternateSetting       5
      bNumEndpoints           1
      bInterfaceClass        14 Video
      bInterfaceSubClass      2 Video Streaming
      bInterfaceProtocol      0 
      iInterface              0 
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x87  EP 7 IN
        bmAttributes            5
          Transfer Type            Isochronous
          Synch Type               Asynchronous
          Usage Type               Data
        wMaxPacketSize     0x0c00  2x 1024 bytes
        bInterval               1
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        1
      bAlternateSetting       6
      bNumEndpoints           1
      bInterfaceClass        14 Video
      bInterfaceSubClass      2 Video Streaming
      bInterfaceProtocol      0 
      iInterface              0 
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x87  EP 7 IN
        bmAttributes            5
          Transfer Type            Isochronous
          Synch Type               Asynchronous
          Usage Type               Data
        wMaxPacketSize     0x1400  3x 1024 bytes
        bInterval               1
nschurando commented 4 years ago

Wouldn't that be because of usb bandwidth limitations?

JamesH65 commented 4 years ago

What's a UVC? (Never assume people know abbreviations in your bug reports). Link to the particular 'UVC' you are using?

ptesarik commented 4 years ago

USB video device class: https://en.wikipedia.org/wiki/USB_video_device_class

P33M commented 4 years ago

When the errors are appearing, what is the output of sudo cat /sys/kernel/debug/usb/devices?

steven-hz commented 4 years ago

Wouldn't that be because of usb bandwidth limitations?

Maybe it is, but how can I confirm this?

steven-hz commented 4 years ago

When the errors are appearing, what is the output of sudo cat /sys/kernel/debug/usb/devices?

This output will be given by next test cycle while now is testing 6 UVCS.

JamesH65 commented 4 years ago

Wouldn't that be because of usb bandwidth limitations?

Maybe it is, but how can I confirm this?

Work out what the bandwidth each device is taking - video is fairly easy to approximate - video size, bit depth/pixel and fps gives you a basic number. Multiply it up by number of devices. Always assume that actual bandwidth of USB is about half the stated theoretical max. Drop a bit more for contention handling. Approximate, but useful numbers.

kbingham commented 4 years ago

Bandwidth could indeed be an issue here. One of my colleagues has made a patch / workaround to be able to manually reduce the bandwith consumed by UVC. It might be worth trying/investigating.

If it solves your problem do let us know, as we're struggling to figure out a good way to solve this for upstream, generic use cases, so any feedback on it actually solving something real will be helpful.

https://www.thegoodpenguin.co.uk/blog/multiple-uvc-cameras-on-linux/