Hi Salvatore,
52fbe173baa4df9d14bd733f42ee6b9ceab8299b is the first bad commit commit 52fbe173baa4df9d14bd733f42ee6b9ceab8299b (HEAD) Author: Ricardo Ribalda <[email protected]> Date: Wed Dec 18 21:39:09 2024 +0000media: uvcvideo: Invert default value for nodrop module param The module param `nodrop` defines what to do with frames that contain an error: drop them or sending them to userspace. The default in the rest of the media subsystem is to return buffers with an error to userspace with V4L2_BUF_FLAG_ERROR set in v4l2_buffer.flags. In UVC we drop buffers with errors by default. Change the default behaviour of uvcvideo to match the rest of the drivers and maybe get rid of the module parameter in the future. Suggested-by: Laurent Pinchart <[email protected]> Signed-off-by: Ricardo Ribalda <[email protected]> Reviewed-by: Laurent Pinchart <[email protected]> Reviewed-by: Hans de Goede <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Laurent Pinchart <[email protected]> Signed-off-by: Mauro Carvalho Chehab <[email protected]> drivers/media/usb/uvc/uvc_driver.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) I added Ricardo in Cc. Ricardo, see https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1121718 for context. The bug does not always immediately manifest, so there is a small chance that for some of the commits that I marked "good", artifacts would have started appearing if I had waited a bit longer. But the commit seems reasonably plausible to be able to cause the kind of error I am seeing. Given that this is about a module parameter, I assume I could test this by booting the latest kernel and setting the parameter back to its previous value... but I don't know enough about how the kernel works to actually do that.^^ Happy to try that if someone gives me some pointers.You can create a modprobe.d file /etc/modprobe.d/uvcvideo.conf with options uvcvideo nodrop=0 to pass 'nodrop=0' parameter when loading the uvcvideo module (then unload and load the module).
Thanks, that seems to have worked! So at least for now this is a viable work-around...
But it already warns in dmesg when doing so with: uvcvideo: [Deprecated]: nodrop parameter will be eventually removed.
... but only until the parameter gets removed, of course. Kind regards, Ralf
Regards, Salvatore
