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Re: Strange webcam failure and 'fix'



On 16/01/2015 04:48, Alexis wrote:

Ping. Any thoughts?


Alexis.

On Thu, 08 Jan 2015 18:53:03 +1100, Alexis wrote:

Hi all,

i have a Logitech Quickcam Pro 9000, which i use with the Jitsi
voice/video client. Occasionally it stops working, such that my laptop
- an Asus K53E running 64-bit Wheezy + all available updates - doesn't
appear to detect it at all (as per the output of
e.g. `lsusb`). Leaving the cam plugged in and soft-restarting the
laptop makes no difference, nor does hard-restarting the
laptop. Unplugging the cam and soft- or hard-restarting the laptop
before plugging it back in makes no difference either.

What /does/ make a difference, however, is simply plugging the cam
into a USB port of a desktop machine - an Ipex Augsburg 0431 running
32-bit Wheezy + all available updates - waiting a few moments, then
unplugging it from the desktop machine and plugging it back into the
laptop, whereupon it's immediately detected and available for use.

Can anyone offer any insights as to what might be happening here?


Alexis.



Hello,

I had one of those and there is a well know, but unfixed, firmware bug affecting most Qc Pro 9000. If you search for "quickcam Pro 9000 firmware bug" you will see what I mean by "well known bug".

I tinkered a lot to get this camera to work and never got a reliable behavior, sometimes the bug shows up very quickly, and at other times it can run for a while properly before freezing.

When it happens you can try unplugging the cam AND unloading/reloading (modprobe) the uvcvideo driver, usually it was doing the trick for me. But since I could not script the unplugging part ;-) I ended up buying a new cam.

I remember reading that forcing the snd_usb_audio to load before uvcvideo is loaded eases the pain. Maybe writing a udev rule or a custom ".conf" file in /etc/modprobe.d, or just a script to unload uvcvideo and snd_usb_audio then reload them in the right order would help. But this is no silver bullet, with my cam it didn't make the freezes go away completely, just gave me more time in between.

My 2 cents.


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