[libcamera-devel] [PATCH] libcamera: camera_sensor: only access V4L_CID_HBLANK if existing

[Laurent Pinchart]

On Wed, Nov 15, 2023 at 03:57:23PM +0100, Jacopo Mondi via libcamera-devel wrote:
> Hi Alain
> 
> On Mon, Nov 13, 2023 at 11:08:51AM +0100, Alain Volmat via libcamera-devel wrote:
> > Correct a crash in CameraSensor::init when trying to set the
> > V4L2_CID_HBLANK control on sensor not implementing this control.
> > The HBLANK sensor not being mandatory for non-RAW sensors, it can
> > happen that the sensor does not expose this control.
> > Perform check against availability of the control prior to usage in
> > order to avoid the crash.
> >
> > Signed-off-by: Alain Volmat <alain.volmat at foss.st.com>
> > ---
> >  src/libcamera/camera_sensor.cpp | 24 +++++++++++++-----------
> >  1 file changed, 13 insertions(+), 11 deletions(-)
> >
> > diff --git a/src/libcamera/camera_sensor.cpp b/src/libcamera/camera_sensor.cpp
> > index d9261672..0ef78d9c 100644
> > --- a/src/libcamera/camera_sensor.cpp
> > +++ b/src/libcamera/camera_sensor.cpp
> > @@ -197,17 +197,19 @@ int CameraSensor::init()
> >  	 * \todo The control API ought to have a flag to specify if a control
> >  	 * is read-only which could be used below.
> >  	 */
> 
> Actually the above comment suggest that there's no way to know if a
> control is RO, while I see
> 
> 	if (hflipInfo && !(hflipInfo->flags & V4L2_CTRL_FLAG_READ_ONLY) &&
> 	    vflipInfo && !(vflipInfo->flags & V4L2_CTRL_FLAG_READ_ONLY))
> 
> in other parts of the class.
> 
> This is unrelated to this change though
> 
> > -	const ControlInfo hblank = ctrls.infoMap()->at(V4L2_CID_HBLANK);
> > -	const int32_t hblankMin = hblank.min().get<int32_t>();
> > -	const int32_t hblankMax = hblank.max().get<int32_t>();
> > -
> > -	if (hblankMin != hblankMax) {
> > -		ControlList ctrl(subdev_->controls());
> > -
> > -		ctrl.set(V4L2_CID_HBLANK, hblankMin);
> > -		ret = subdev_->setControls(&ctrl);
> > -		if (ret)
> > -			return ret;
> > +	if (ctrls.infoMap()->find(V4L2_CID_HBLANK) != ctrls.infoMap()->end()) {
> 
> Most YUV/RGB sensor drivers I know of do not support HBLANK, so I
> would have expected this issue to be hit earlier than this. Possibly
> libcamera is not very populare with YUV/RGB sensor :)
> 
> > +		const ControlInfo hblank = ctrls.infoMap()->at(V4L2_CID_HBLANK);
> > +		const int32_t hblankMin = hblank.min().get<int32_t>();
> > +		const int32_t hblankMax = hblank.max().get<int32_t>();
> > +
> > +		if (hblankMin != hblankMax) {
> > +			ControlList ctrl(subdev_->controls());
> > +
> > +			ctrl.set(V4L2_CID_HBLANK, hblankMin);
> > +			ret = subdev_->setControls(&ctrl);
> > +			if (ret)
> > +				return ret;
> > +		}
> 
> The patch looks good to me
> Reviewed-by: Jacopo Mondi <jacopo.mondi at ideasonboard.com>

Likewise;

Reviewed-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>

> >  	}
> >
> >  	return applyTestPatternMode(controls::draft::TestPatternModeEnum::TestPatternModeOff);

-- 
Regards,

Laurent Pinchart