My thread has not the same issue like (post#1448 and post#1526), but nearly…
I have a dispVM and connecting my built-in camera to this VM in “Qubes Devices”. I open via Firefox (or Chromium) the Webpage Jitsi. I will asked for audio permission and then camera permission. If I give the grant for camera permission “Qubes VCHAN source”, then the system tries to establish the channel and … puff… no pic, only my on-air-LED is shining and a error message appears via pop-up notification from the dom0 system. I remove the usb-connection to this dispVM and add it again… after serveral times of switching on/off I get a stable communication between my web browser and camera.
Strange, right? What could I do to analyze it in a professional way?
Your posts suggest that you are at least somewhat familiar with Linux-based OSes, and you appear to be somewhat familiar with Qubes OS (which is awesome, by the way).
So what information do you think would be helpful to know to help you diagnose and solve this?
The output of lsusb, maybe?
The make and model of your webcam, maybe?
user@disp1833:~$ sudo lsusb
Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 001 Device 008: ID 0bda:58db Realtek Semiconductor Corp. Integrated Camera
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
I tried in dom0 to get some messages (e.g. tail -f /var/log/* )… nothing.
I tried in dispVM to get some messages (e.g. tail -f /var/log/syslog)… gotcha!
For explaination… USB device (built-in camera) was already connected to the dispVM. I disconneted it and tried again to connect it. I was in a Jitsi room, the whole time…
That’s what’s supposed to happen. Ideally, dom0 shouldn’t even know that your camera exists.
That could potentially be why (maybe). Jitsi sometimes doesn’t like certain webcams, particularly if you’re self-hosting the videobridge (I found that out the hard way…).
Does the camera work in other applications, for example, Cheese or VLC?