How to diagnose webcam uptime issue

[Martin Gladdish]

Hi folks,

I've been running Qubes as my main dev workstation (on a Lenovo T590) for a good few months now and I've got nearly everything working as I need. The final niggle is an intermittent webcam issue.

The webcam is recognised fine and I can assign it to my Qube just fine.

I can start a Google Meet session and everything's just dandy.

But after a while (10-20 mins?) Firefox will al of a sudden think it no longer has a camera available and will no longer send video.

* The witness light on the camera is still on, so the laptop thinks *something* is using it

* If I try to unmount the camera (it's listed as a USB device) via the Qubes Devices systray icon I get an error saying "Detaching device ... failed. Error: 'device 4-8 of class usb not attached to {qube-name}"

* I can restart my usb qube which clears the camera's witness light as well as the qube mount, and I'm free to re-mount the camera to my qube again. But Firefox still doesn't recognise it.

* After an hour or so, rebooting the usb qube does sort everything out and I can use video in a Google Meet again.

Where can I start looking to diagnose what's going on?

Many thanks,

Martin Gladdish.

[Martin Gladdish]

Interestingly, the behaviour's different when using the tasktray icon vs the command line.

I've found when the camera has stopped working it's showing as still assigned in the tasktray tool, but dom0's qvm-usb command thinks it's not assigned.

If I then use qvm-usb to re-assign it, then it starts working again.

Weird.

It still drops out after a while though - I had to use the command line to re-attach it 3 times on my 1 hour conf call this morning.