XPost: linux.debian.bugs.dist   
   From: post@ralfj.de   
      
   This is a multi-part MIME message sent by reportbug.   
      
      
   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.   
      
   Kind regards,   
   Ralf Jung   
      
   Output of "lsusb -v -d 046d:0892":   
      
   Bus 003 Device 070: ID 046d:0892 Logitech, Inc. C920 HD Pro Webcam   
   Negotiated speed: High Speed (480Mbps)   
   Device Descriptor:   
     bLength                18   
     bDescriptorType         1   
     bcdUSB               2.00   
     bDeviceClass          239 Miscellaneous Device   
     bDeviceSubClass         2 [unknown]   
     bDeviceProtocol         1 Interface Association   
     bMaxPacketSize0        64   
     idVendor           0x046d Logitech, Inc.   
     idProduct          0x0892 C920 HD Pro Webcam   
     bcdDevice            0.19   
     iManufacturer           0   
     iProduct                2 HD Pro Webcam C920   
     iSerial                 1 B59E40EF   
     bNumConfigurations      1   
     Configuration Descriptor:   
       bLength                 9   
       bDescriptorType         2   
       wTotalLength       0x09c3   
       bNumInterfaces          4   
       bConfigurationValue     1   
       iConfiguration          0   
       bmAttributes         0x80   
         (Bus Powered)   
       MaxPower              500mA   
       Interface Association:   
         bLength                 8   
         bDescriptorType        11   
         bFirstInterface         0   
         bInterfaceCount         2   
         bFunctionClass         14 Video   
         bFunctionSubClass       3 Video Interface Collection   
         bFunctionProtocol       0   
         iFunction               0   
       Interface Descriptor:   
         bLength                 9   
         bDescriptorType         4   
         bInterfaceNumber        0   
         bAlternateSetting       0   
         bNumEndpoints           1   
         bInterfaceClass        14 Video   
         bInterfaceSubClass      1 Video Control   
         bInterfaceProtocol      0   
         iInterface              0   
         VideoControl Interface Descriptor:   
           bLength                13   
           bDescriptorType        36   
           bDescriptorSubtype      1 (HEADER)   
           bcdUVC               1.00   
           wTotalLength       0x00d6   
           dwClockFrequency       30.000000MHz   
           bInCollection           1   
           baInterfaceNr( 0)       1   
         VideoControl Interface Descriptor:   
           bLength                18   
           bDescriptorType        36   
           bDescriptorSubtype      2 (INPUT_TERMINAL)   
           bTerminalID             1   
           wTerminalType      0x0201 Camera Sensor   
           bAssocTerminal          0   
           iTerminal               0   
           wObjectiveFocalLengthMin      0   
           wObjectiveFocalLengthMax      0   
           wOcularFocalLength            0   
           bControlSize                  3   
           bmControls           0x00020a2e   
             Auto-Exposure Mode   
             Auto-Exposure Priority   
             Exposure Time (Absolute)   
             Focus (Absolute)   
             Zoom (Absolute)   
             PanTilt (Absolute)   
             Focus, Auto   
         VideoControl Interface Descriptor:   
           bLength                11   
           bDescriptorType        36   
           bDescriptorSubtype      5 (PROCESSING_UNIT)   
         Warning: Descriptor too short   
           bUnitID                 3   
           bSourceID               1   
           wMaxMultiplier      16384   
           bControlSize            2   
           bmControls     0x0000175b   
             Brightness   
             Contrast   
             Saturation   
             Sharpness   
             White Balance Temperature   
             Backlight Compensation   
             Gain   
             Power Line Frequency   
             White Balance Temperature, Auto   
           iProcessing             0   
           bmVideoStandards     0x1b   
             None   
             NTSC - 525/60   
             SECAM - 625/50   
             NTSC - 625/50   
         VideoControl Interface Descriptor:   
           bLength                27   
           bDescriptorType        36   
           bDescriptorSubtype      6 (EXTENSION_UNIT)   
           bUnitID                 6   
           guidExtensionCode         {23e49ed0-1178-4f31-ae52-d2fb8a8d3b48}   
           bNumControls           10   
           bNrInPins               1   
           baSourceID( 0)          3   
           bControlSize            2   
           bmControls( 0)       0xff   
           bmControls( 1)       0x03   
           iExtension              0   
         VideoControl Interface Descriptor:   
           bLength                27   
           bDescriptorType        36   
           bDescriptorSubtype      6 (EXTENSION_UNIT)   
           bUnitID                 8   
           guidExtensionCode         {69678ee4-410f-40db-a850-7420d7d8240e}   
           bNumControls            7   
           bNrInPins               1   
           baSourceID( 0)          3   
           bControlSize            2   
           bmControls( 0)       0x3b   
           bmControls( 1)       0x03   
           iExtension              0   
         VideoControl Interface Descriptor:   
      
   [continued in next message]   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)