From: chenchangcheng Date: Sat, 10 May 2025 06:18:03 +0000 (+0800) Subject: media: uvcvideo: Fix bandwidth issue for Alcor camera X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=9764401bf6f8a20eb11c2e78470f20fee91a9ea7;p=users%2Fjedix%2Flinux-maple.git media: uvcvideo: Fix bandwidth issue for Alcor camera Some broken device return wrong dwMaxPayloadTransferSize fields as follows: [ 218.632537] uvcvideo: Device requested 2752512 B/frame bandwidth. [ 218.632598] uvcvideo: No fast enough alt setting for requested bandwidth. When dwMaxPayloadTransferSize is greater than maxpsize, it will prevent the camera from starting. So use the bandwidth of maxpsize. Signed-off-by: chenchangcheng Reviewed-by: Ricardo Ribalda Reviewed-by: Laurent Pinchart Link: https://lore.kernel.org/r/20250510061803.811433-1-ccc194101@163.com Signed-off-by: Laurent Pinchart Signed-off-by: Hans Verkuil --- diff --git a/drivers/media/usb/uvc/uvc_video.c b/drivers/media/usb/uvc/uvc_video.c index e3567aeb0007..11769a1832d2 100644 --- a/drivers/media/usb/uvc/uvc_video.c +++ b/drivers/media/usb/uvc/uvc_video.c @@ -262,6 +262,15 @@ static void uvc_fixup_video_ctrl(struct uvc_streaming *stream, ctrl->dwMaxPayloadTransferSize = bandwidth; } + + if (stream->intf->num_altsetting > 1 && + ctrl->dwMaxPayloadTransferSize > stream->maxpsize) { + dev_warn_ratelimited(&stream->intf->dev, + "UVC non compliance: the max payload transmission size (%u) exceeds the size of the ep max packet (%u). Using the max size.\n", + ctrl->dwMaxPayloadTransferSize, + stream->maxpsize); + ctrl->dwMaxPayloadTransferSize = stream->maxpsize; + } } static size_t uvc_video_ctrl_size(struct uvc_streaming *stream)