On Thu, Nov 28, 2024 at 08:53:41PM +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
Reviewed-by: Laurent Pinchart laurent.pinchart@ideasonboard.com
drivers/media/usb/uvc/uvc_video.c | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+)
diff --git a/drivers/media/usb/uvc/uvc_video.c b/drivers/media/usb/uvc/uvc_video.c index cd9c29532fb0..67f714bca417 100644 --- a/drivers/media/usb/uvc/uvc_video.c +++ b/drivers/media/usb/uvc/uvc_video.c @@ -79,6 +79,27 @@ int uvc_query_ctrl(struct uvc_device *dev, u8 query, u8 unit, if (likely(ret == size)) return 0;
- /*
* Some devices return shorter USB control packets than expected if the* returned value can fit in less bytes. Zero all the bytes that the* device has not written.** This quirk is applied to all controls, regardless of their data type.* Most controls are little-endian integers, in which case the missing* bytes become 0 MSBs. For other data types, a different heuristic* could be implemented if a device is found needing it.** 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",