Re: [linux-uvc-devel] Issues with Logitech C920

Am 24.01.2013 10:20, schrieb Benjamin Hodgetts:
> I purchased this webcam the other day and I'm trying to diagnose whether
> it's broken or just "has issues" on Linux at present.
>
> Firstly, the webcam on the machine I intend to use it on doesn't work at
> all (plugged directly into the machine, not via a hub). Either on boot
> it'll report:
> 	usb 3-1.1: new high-speed USB device number 7 using ehci_hcd
> 	usb 3-1.1: device not accepting address 7, error -110
>
> and manually re-plugging the device, it shows up (and gets an address)
> but if I try and use it it fails with:
> 	uvcvideo: Failed to set UVC probe control : -110 (exp. 26).

110 means ETIMEOUT. This error happens on usb level, not uvcvideo.
Since this camera is well supported, there are fallowing options:
- some usb driver issues. test some previous kernel version. Or make 
sure it works with windows without extra installed drivers. It is uvc 
cam, it should just work.
- if is not working with other machine too, then most probably bad 
device or broken cable. in this case send it back!


> Now when trying the webcam on another machine I at least managed to get
> it to work, but generally only once before the UVC commands started
> failing (IO errors). I would have to physically disconnect it and
> reconnect it to get it to work again. I could also generally only issue
> a single v4l2 command to it before it became unreachable again. It was
> fine if I left video streaming, but closing the connection and trying
> again is what breaks it.
>
> Details regarding the device are below (it's currently plugged into a
> powered hub to see if that would help. It didn't). One thing that I
> found stood out though was that lsusb -v states that the device is
> self-powered when it should be bus-powered.

hmm... that is weird. Like i said, you should test different software 
(widows or kernel version) to exclude one of options.

-- 
Regards,
Oleksij