media: uvcvideo: Fix bandwidth issue for Alcor camera

[ Upstream commit 9764401bf6 ]

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 <chenchangcheng@kylinos.cn>
Reviewed-by: Ricardo Ribalda <ribalda@chromium.org>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Link: https://lore.kernel.org/r/20250510061803.811433-1-ccc194101@163.com
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
chenchangcheng 2025-05-10 14:18:03 +08:00 committed by Greg Kroah-Hartman
parent 17b30e5ded
commit eb6059474e

View File

@ -231,6 +231,15 @@ 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)