On 11/03/2021 23:19, Ricardo Ribalda wrote:
> According to the doc:
> The, in hindsight quite poor, solution for that is to set error_idx to
> count if the validation failed.
I think this needs a bit more explanation. How about this:
"If an error is found when validating the list of controls passed with
VIDIOC_G_EXT_CTRLS, then error_idx shall be set to ctrls->count to indicate
to userspace that no actual hardware was touched.
It would have been much nicer of course if error_idx could point to the
control index that failed the validation, but sadly that's not how the
API was designed."
>
> Fixes v4l2-compliance:
> Control ioctls (Input 0):
> fail: v4l2-test-controls.cpp(645): invalid error index write only control
> test VIDIOC_G/S/TRY_EXT_CTRLS: FAIL
>
> Signed-off-by: Ricardo Ribalda <ribalda@xxxxxxxxxxxx>
After improving the commit log you can add my:
Reviewed-by: Hans Verkuil <hverkuil-cisco@xxxxxxxxx>
Thanks!
Hans
> ---
> drivers/media/usb/uvc/uvc_v4l2.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/media/usb/uvc/uvc_v4l2.c b/drivers/media/usb/uvc/uvc_v4l2.c
> index 157310c0ca87..36eb48622d48 100644
> --- a/drivers/media/usb/uvc/uvc_v4l2.c
> +++ b/drivers/media/usb/uvc/uvc_v4l2.c
> @@ -1073,7 +1073,8 @@ static int uvc_ioctl_g_ext_ctrls(struct file *file, void *fh,
> ret = uvc_ctrl_get(chain, ctrl);
> if (ret < 0) {
> uvc_ctrl_rollback(handle);
> - ctrls->error_idx = i;
> + ctrls->error_idx = (ret == -EACCES) ?
> + ctrls->count : i;
> return ret;
> }
> }
>
