Hi Ricardo,
Thank you for the patch.
On Mon, Nov 18, 2024 at 05:16:51PM +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()") Signed-off-by: Ricardo Ribalda ribalda@chromium.org
drivers/media/usb/uvc/uvc_video.c | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-)
diff --git a/drivers/media/usb/uvc/uvc_video.c b/drivers/media/usb/uvc/uvc_video.c index cd9c29532fb0..e165850397a0 100644 --- a/drivers/media/usb/uvc/uvc_video.c +++ b/drivers/media/usb/uvc/uvc_video.c @@ -76,8 +76,22 @@ int uvc_query_ctrl(struct uvc_device *dev, u8 query, u8 unit, ret = __uvc_query_ctrl(dev, query, unit, intfnum, cs, data, size, UVC_CTRL_CONTROL_TIMEOUT);
- if (likely(ret == size))
- if (ret > 0) {
if (size == ret)return 0;
Why is this within the ret > 0 block ? I would write
if (likely(ret == size)) return 0;
if (ret > 0) {
/** In UVC the data is represented in little-endian by default.
By default, or always ?
* Some devices return shorter control packages that expected
What's a "control package" ?
I think you meants "than expected", not "that expected".
* if the return value can fit in less bytes.* Zero all the bytes that the device have not written.*/
Do we want to apply this workaround to GET_INFO and GET_LEN, or can we restrict it to GET_CUR, GET_MIN, GET_MAX and GET_RES ?
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);- }
if (ret != -EPIPE) { dev_err(&dev->udev->dev,