From: Ricardo Ribalda Date: Tue, 21 Oct 2025 10:36:17 +0000 (+0000) Subject: media: uvcvideo: Use heuristic to find stream entity X-Git-Tag: v6.1.169~46 X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=8ec9198bac7c2d6dd3dbf63cdfa84ceb230d999d;p=thirdparty%2Fkernel%2Fstable.git media: uvcvideo: Use heuristic to find stream entity [ Upstream commit 758dbc756aad429da11c569c0d067f7fd032bcf7 ] Some devices, like the Grandstream GUV3100 webcam, have an invalid UVC descriptor where multiple entities share the same ID, this is invalid and makes it impossible to make a proper entity tree without heuristics. We have recently introduced a change in the way that we handle invalid entities that has caused a regression on broken devices. Implement a new heuristic to handle these devices properly. Reported-by: Angel4005 Closes: https://lore.kernel.org/linux-media/CAOzBiVuS7ygUjjhCbyWg-KiNx+HFTYnqH5+GJhd6cYsNLT=DaA@mail.gmail.com/ Fixes: 0e2ee70291e6 ("media: uvcvideo: Mark invalid entities with id UVC_INVALID_ENTITY_ID") Cc: stable@vger.kernel.org Signed-off-by: Ricardo Ribalda Reviewed-by: Hans de Goede Signed-off-by: Hans Verkuil Signed-off-by: Sasha Levin --- diff --git a/drivers/media/usb/uvc/uvc_driver.c b/drivers/media/usb/uvc/uvc_driver.c index f81bddd20bc09..a1c6ae97a2b93 100644 --- a/drivers/media/usb/uvc/uvc_driver.c +++ b/drivers/media/usb/uvc/uvc_driver.c @@ -164,13 +164,26 @@ static struct uvc_entity *uvc_entity_by_reference(struct uvc_device *dev, static struct uvc_streaming *uvc_stream_by_id(struct uvc_device *dev, int id) { - struct uvc_streaming *stream; + struct uvc_streaming *stream, *last_stream; + unsigned int count = 0; list_for_each_entry(stream, &dev->streams, list) { + count += 1; + last_stream = stream; if (stream->header.bTerminalLink == id) return stream; } + /* + * If the streaming entity is referenced by an invalid ID, notify the + * user and use heuristics to guess the correct entity. + */ + if (count == 1 && id == UVC_INVALID_ENTITY_ID) { + dev_warn(&dev->intf->dev, + "UVC non compliance: Invalid USB header. The streaming entity has an invalid ID, guessing the correct one."); + return last_stream; + } + return NULL; }