On Tue, 26 Nov 2024 at 19:06, Laurent Pinchart laurent.pinchart@ideasonboard.com wrote:
On Wed, Nov 20, 2024 at 03:26:19PM +0000, Ricardo Ribalda wrote:
Some cameras, like the ELMO MX-P3, do not return all the bytes requested from a control if it can fit in less bytes. Eg: Returning 0xab instead of 0x00ab. usb 3-9: Failed to query (GET_DEF) UVC control 3 on unit 2: 1 (exp. 2).
Extend the returned value from the camera and return it.
Cc: stable@vger.kernel.org Fixes: a763b9fb58be ("media: uvcvideo: Do not return positive errors in uvc_query_ctrl()") Reviewed-by: Hans de Goede hdegoede@redhat.com Signed-off-by: Ricardo Ribalda ribalda@chromium.org
drivers/media/usb/uvc/uvc_video.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+)
diff --git a/drivers/media/usb/uvc/uvc_video.c b/drivers/media/usb/uvc/uvc_video.c index cd9c29532fb0..482c4ceceaac 100644 --- a/drivers/media/usb/uvc/uvc_video.c +++ b/drivers/media/usb/uvc/uvc_video.c @@ -79,6 +79,22 @@ int uvc_query_ctrl(struct uvc_device *dev, u8 query, u8 unit, if (likely(ret == size)) return 0;
/** In UVC the data is usually represented in little-endian.I had a comment about this in the previous version, did you ignore it on purpose because you disagreed, or was it an oversight ?
I rephrased the comment. I added "usually" to make it clear that it might not be the case for all the data types. Like composed or xu. I also r/package/packet/
Did I miss another comment?
* Some devices return shorter USB control packets that expected if the* returned value can fit in less bytes. Zero all the bytes that the* device have not written.s/have/has/
And if you meant to start a new paragraph here, a blank line is missing. Otherwise, no need to break the line before 80 columns.
The patch is already in the uvc tree. How do you want to handle this?
* We exclude UVC_GET_INFO from the quirk. UVC_GET_LEN does not need to* be excluded because its size is always 1.*/if (ret > 0 && query != UVC_GET_INFO) {memset(data + ret, 0, size - ret);dev_warn_once(&dev->udev->dev,"UVC non compliance: %s control %u on unit %u returned %d bytes when we expected %u.\n",uvc_query_name(query), cs, unit, ret, size);return 0;}if (ret != -EPIPE) { dev_err(&dev->udev->dev, "Failed to query (%s) UVC control %u on unit %u: %d (exp. %u).\n",-- Regards,
Laurent Pinchart