On (21/03/24 12:00), Tomasz Figa wrote:
[..]
> > I guess in our case we need to talk about rectangle,auto-controls tuple
> > that we send to firmware
> >
> > rect {
> > (0, 0), (INT_MAX, INT_MAX)
> > }
> > auto-controls {
> > INT_MAX
> > }
> >
> > For ROI user-space also must provide valid auto-controls value, which
> > normally requires GET_MIN/GET_MAX discovery.
> >
> > v4l2 selection API mentions only rectangle adjustments and errnos like
> > -ERANGE also mention "It is not possible to adjust struct v4l2_rect r
> > rectangle to satisfy all constraints given in the flags argument".
> >
> > So in case when auto-controls is out of supported range (out of
> > GET_MIN, GET_MAX range) there is no way for us to tell user-space that
> > auto-controls is wrong. We probably need silently pick up the first
> > supported value, but not sure how well this will work out in the end.
>
> Shouldn't the autocontrol selection be done via a separate bitmask
> control rather than some custom flags in the selection API?
That selection must be done before we send ROI to the firmware.
Firmware H that I have supports split controls - we can send
ROI::rectangle and ROI::autocontrols separately. But other
firmwares don't tolerate such a thing and by the time we issue
uvc_query_ctrl(stream->dev,
UVC_SET_CUR
UVC_CT_REGION_OF_INTEREST_CONTROL
roi,
+ sizeof(struct uvc_roi_rect))
roi rectangle should be of size 5 * u16 and contain values that firmware
will accept, including autocontrols.
