XPost: linux.debian.bugs.dist   
   From: carnil@debian.org   
      
   Control: tags -1 + moreinfo   
      
   Hi Ralf,   
      
   On Mon, Dec 01, 2025 at 10:34:52AM +0100, Ralf Jung wrote:   
   > Package: src:linux   
   > Version: 6.17.8-1   
   > Severity: normal   
   > X-Debbugs-Cc: debian-amd64@lists.debian.org   
   > User: debian-amd64@lists.debian.org   
   > Usertags: amd64   
   >   
   > Dear Maintainer,   
   >   
   > Since a recent kernel update, my webcam stopped working properly. The webcam   
   > model is "Logitech C920 HD Pro" (USB ID 046d:0892); I will put the full lsusb   
   > output below. What happens is that, when I am in a Zoom call, after someone   
   else   
   > joins the call, flickering artifacts start to appear: the bottom half of the   
   > image turns gray. I will attach an image. I have so far not been able to   
   > reproduce this outside of Zoom. I tried Jitsi in the browser and Gnome   
   Cheese.   
   > (Zoom does *something* with the webcam when someone joins the call: the exact   
   > frame of the webcam, i.e. how much of the room I see and where the image cuts   
   > off, changes. I have no idea what that is about.)   
   >   
   > I tried playing around with power_line_frequency; that did not help at all.   
   >   
   > This only started recently. I tried booting a 6.12 kernel (with the same   
   > userspace), that fixed the issue -- so it very much looks like a kernel   
   issue to   
   > me. The issue is also present in 6.16, so it's a regression introduced some   
   time   
   > between 6.12 and 6.16. I use Zoom fairly regularly professionally, so this   
   bug   
   > means I am pretty much stuck with a 6.12 kernel for now.   
      
   If you reliably can reproduce the issue then (although I realize that   
   each testing step is time consuming), I would suggest to start a   
   bisect.   
      
   First though narrow down more closely the Debian versions which expose   
   the problen and not (using the images fetched from   
   https://snapshot.debian.org/). Once you have two upstream versions   
   close enough, start a bisect.   
      
   Do you need instructions/help on how to do that?   
      
   Regards,   
   Salvatore   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)