*fascinating* - it works fine when plugged into the USB port in the back 
of my machine, but not in the front. Thanks for all your advice.

Andy

----------------------------------------------------------------------
Andrew J Perrin - andrew_perrin (at) unc.edu - http://perrin.socsci.unc.edu
Associate Professor of Sociology; Book Review Editor, _Social Forces_
University of North Carolina - CB#3210, Chapel Hill, NC 27599-3210 USA



On Tue, 15 Jan 2008, Laurent Pinchart wrote:

> Hi Andrew,
>
> On Tuesday 15 January 2008, Andrew Perrin wrote:
>> On Tue, 15 Jan 2008, Laurent Pinchart wrote:
>>> Hi Andrew,
>>>
>>> On Tuesday 15 January 2008, Andrew Perrin wrote:
>>>> I have a quickcam 9000 pro working fine with luvcview, but it gives the
>>>> famous "black rectangle" with Skype. This is the latest (166) rev. of
>>>> uvcvideo. These messages are in the log when I try:
>>>>
>>>> Jan 14 19:53:08 joehill kernel: ohci_hcd 0000:00:0b.0: leak ed f74175c0
>>>> (#81) state 2
>>>> Jan 14 19:53:22 joehill kernel: uvcvideo: Failed to submit URB 0 (-28).
>>>> Jan 14 19:53:30 joehill kernel: ohci_hcd 0000:00:0b.0: leak ed f7417600
>>>> (#81) state 2
>>>
>>> -28 is -ENOSPC. It means using the device would exceed the available USB
>>> bus bandwidth. If your webcam is plugged into a hub try moving it to a
>>> root port. Make sure you're using an EHCI controller.
>>>
>>> Best regards,
>>>
>>> Laurent Pinchart
>>
>> Very interesting, and thanks for your quick reply. Plugging it directly
>> into the USB port (instead of through a hub) makes both luvcview *and
>> Skype* give a very flickery, but recognizable, image. luvcview dies after
>> a few seconds with the result:
>>
>> Ignoring empty buffer ...
>> Ignoring empty buffer ...
>> Ignoring empty buffer ...
>> Ignoring empty buffer ...
>> Unable to dequeue buffer (22).
>> Error grabbing
>>   Clean Up done Quit
>>
>> ...while Skype just keeps the flickery image on.  /var/log/syslog
>> contains:
>>
>> usb 1-6: new high speed USB device using ehci_hcd and address 9
>> usb 1-6:  configuration #1 chosen from 1 choice
>> uvcvideo: Found UVC 1.00 device <unnamed> (046d:0990)
>> usb 1-6: USB disconnect, address 9
>> usb 1-6: new high speed USB device using ehci_hcd and address 10
>> usb 1-6: device descriptor read/all, error -71
>
> Your webcam seem to be very flaky. Failing to respond to the first GET
> DESCRIPTOR request with -71 means serious hardware trouble.
>
>> usb 1-6: new high speed USB device using ehci_hcd and address 11
>> usb 1-6: configuration #1 chosen from 1 choice
>> uvcvideo: Found UVC 1.00 device <unnamed> (046d:0990)
>> uvcvideo: Failed to query (131) UVC control 1 (unit 0) : -71 (exp. 26).
>> uvcvideo: Failed to query (131) UVC control 1 (unit 0) : -71 (exp. 26).
>
> You should check your cables. Is your computer in an extremely noisy
> environment (electrically speaking) ? Do you experience the same kind of
> trouble with other USB devices ?
>
> Best regards,
>
> Laurent Pinchart
>
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