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[Sancho <sancho@xxxxxxxxx>]

Public bug reported:

I have a strange problem with webcams Creative Live! Cam Sync HD VF0770 (041e:4095).
I have two of them.
I would like to stream simultaneous streams with 1280x720 at 5fps.
When connected directly to laptop, I can do this, actually I can stream the same resolution at 30fps.
But, when I plug both of them using USB hub (Gembird 7-port USB2.0 powered hub), I can stream one camera.
But when starting the second one, the dmesg throws error

uvcvideo: Failed to submit URB 0 (-28).

and the mjpg-streamer shows

Unable to start capture: No space left on device

>From other defects reported here I understand that this is a problem with USB bandwidth allocation.
However, the USB for both cameras seems to be set at 480Mbit - this is the output of lsusb -v -t

/:  Bus 01.Port 1: Dev 1, Class=root_hub, Driver=ehci-pci/5p, 480M
    |__ Port 4: Dev 19, If 0, Class=hub, Driver=hub/4p, 480M
        |__ Port 2: Dev 24, If 0, Class='bInterfaceClass 0x0e not yet handled', Driver=uvcvideo, 480M
        |__ Port 2: Dev 24, If 1, Class='bInterfaceClass 0x0e not yet handled', Driver=uvcvideo, 480M
        |__ Port 2: Dev 24, If 2, Class=audio, Driver=, 480M
        |__ Port 2: Dev 24, If 3, Class=audio, Driver=, 480M
        |__ Port 3: Dev 20, If 0, Class='bInterfaceClass 0x0e not yet handled', Driver=uvcvideo, 480M
        |__ Port 3: Dev 20, If 1, Class='bInterfaceClass 0x0e not yet handled', Driver=uvcvideo, 480M
        |__ Port 3: Dev 20, If 2, Class=audio, Driver=, 480M
        |__ Port 3: Dev 20, If 3, Class=audio, Driver=, 480M
        |__ Port 4: Dev 21, If 0, Class=hub, Driver=hub/4p, 480M

I tried lowering the resolution for both cams to 320x240, minimum fps for the camera is 5, so I can't go any lower than that.
Can anyone, please, point me out how can I investigate this problem further?

** Affects: linux (Ubuntu)
     Importance: Undecided
         Status: New

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https://bugs.launchpad.net/bugs/1227583

Title:
  Webcam USB bandwidth problem when connected using USB2.0 hub

Status in “linux” package in Ubuntu:
  New

Bug description:
  I have a strange problem with webcams Creative Live! Cam Sync HD VF0770 (041e:4095).
  I have two of them.
  I would like to stream simultaneous streams with 1280x720 at 5fps.
  When connected directly to laptop, I can do this, actually I can stream the same resolution at 30fps.
  But, when I plug both of them using USB hub (Gembird 7-port USB2.0 powered hub), I can stream one camera.
  But when starting the second one, the dmesg throws error

  uvcvideo: Failed to submit URB 0 (-28).

  and the mjpg-streamer shows

  Unable to start capture: No space left on device

  From other defects reported here I understand that this is a problem with USB bandwidth allocation.
  However, the USB for both cameras seems to be set at 480Mbit - this is the output of lsusb -v -t

  /:  Bus 01.Port 1: Dev 1, Class=root_hub, Driver=ehci-pci/5p, 480M
      |__ Port 4: Dev 19, If 0, Class=hub, Driver=hub/4p, 480M
          |__ Port 2: Dev 24, If 0, Class='bInterfaceClass 0x0e not yet handled', Driver=uvcvideo, 480M
          |__ Port 2: Dev 24, If 1, Class='bInterfaceClass 0x0e not yet handled', Driver=uvcvideo, 480M
          |__ Port 2: Dev 24, If 2, Class=audio, Driver=, 480M
          |__ Port 2: Dev 24, If 3, Class=audio, Driver=, 480M
          |__ Port 3: Dev 20, If 0, Class='bInterfaceClass 0x0e not yet handled', Driver=uvcvideo, 480M
          |__ Port 3: Dev 20, If 1, Class='bInterfaceClass 0x0e not yet handled', Driver=uvcvideo, 480M
          |__ Port 3: Dev 20, If 2, Class=audio, Driver=, 480M
          |__ Port 3: Dev 20, If 3, Class=audio, Driver=, 480M
          |__ Port 4: Dev 21, If 0, Class=hub, Driver=hub/4p, 480M

  I tried lowering the resolution for both cams to 320x240, minimum fps for the camera is 5, so I can't go any lower than that.
  Can anyone, please, point me out how can I investigate this problem further?

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