On 26/03/2021 10:58, Ricardo Ribalda wrote: > The uvc driver relies on the camera firmware to keep the control states > and therefore is not capable of changing an inactive control. > > Allow returning -EACESS in those cases. -EACCES > > Signed-off-by: Ricardo Ribalda <ribalda@xxxxxxxxxxxx> > --- > Documentation/userspace-api/media/v4l/vidioc-g-ctrl.rst | 5 +++++ > Documentation/userspace-api/media/v4l/vidioc-g-ext-ctrls.rst | 5 +++++ > 2 files changed, 10 insertions(+) > > diff --git a/Documentation/userspace-api/media/v4l/vidioc-g-ctrl.rst b/Documentation/userspace-api/media/v4l/vidioc-g-ctrl.rst > index 4f1bed53fad5..8c0a203385c2 100644 > --- a/Documentation/userspace-api/media/v4l/vidioc-g-ctrl.rst > +++ b/Documentation/userspace-api/media/v4l/vidioc-g-ctrl.rst > @@ -95,3 +95,8 @@ EBUSY > > EACCES > Attempt to set a read-only control or to get a write-only control. > + > + Or if there is an attempt to set an inactive control and the driver is > + not capable of keeping the new value until the control is active again. keeping: 'caching' or 'storing' are better words, I think. > + This is the case for drivers that do not use the standard control > + framework and rely purely on the hardware to keep the controls' state. I would drop that last sentence. It is not relevant information to the users of the API. > diff --git a/Documentation/userspace-api/media/v4l/vidioc-g-ext-ctrls.rst b/Documentation/userspace-api/media/v4l/vidioc-g-ext-ctrls.rst > index b9c62affbb5a..bb7de7a25241 100644 > --- a/Documentation/userspace-api/media/v4l/vidioc-g-ext-ctrls.rst > +++ b/Documentation/userspace-api/media/v4l/vidioc-g-ext-ctrls.rst > @@ -438,3 +438,8 @@ EACCES > > Or the ``which`` field was set to ``V4L2_CTRL_WHICH_REQUEST_VAL`` but the > device does not support requests. > + > + Or if there is an attempt to set an inactive control and the driver is > + not capable of keeping the new value until the control is active again. > + This is the case for drivers that do not use the standard control > + framework and rely purely on the hardware to keep the controls' state. Same comments as above. > Regards, Hans
