[libcamera-devel] [PATCH 09/13] libcamera: pipeline: simple: Reset routing table of subdevs

[Laurent Pinchart]

Hi Tomi,

On Tue, Aug 02, 2022 at 02:05:16PM +0300, Tomi Valkeinen wrote:
> On 01/08/2022 03:05, Laurent Pinchart via libcamera-devel wrote:
> > From: Jacopo Mondi <jacopo at jmondi.org>
> > 
> > Reset the routing table of subdevices supporting the V4L2 streams API to
> > its default state when initializing the pipeline handler. This avoids
> > issues caused by usage of leftover state.
> > 
> > Signed-off-by: Jacopo Mondi <jacopo at jmondi.org>
> > Signed-off-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
> > ---
> >   src/libcamera/pipeline/simple/simple.cpp | 49 ++++++++++++++++++++++++
> >   1 file changed, 49 insertions(+)
> > 
> > diff --git a/src/libcamera/pipeline/simple/simple.cpp b/src/libcamera/pipeline/simple/simple.cpp
> > index bc0cb1a00c2a..731d355efda6 100644
> > --- a/src/libcamera/pipeline/simple/simple.cpp
> > +++ b/src/libcamera/pipeline/simple/simple.cpp
> > @@ -332,6 +332,7 @@ private:
> >   	}
> >   
> >   	std::vector<MediaEntity *> locateSensors();
> > +	static int resetRoutingTable(V4L2Subdevice *subdev);
> >   
> >   	const MediaPad *acquirePipeline(SimpleCameraData *data);
> >   	void releasePipeline(SimpleCameraData *data);
> > @@ -1260,6 +1261,37 @@ std::vector<MediaEntity *> SimplePipelineHandler::locateSensors()
> >   	return sensors;
> >   }
> >   
> > +int SimplePipelineHandler::resetRoutingTable(V4L2Subdevice *subdev)
> > +{
> > +	/* Reset the media entity routing table to its default state. */
> > +	V4L2Subdevice::Routing routing = {};
> > +
> > +	int ret = subdev->getRouting(&routing, V4L2Subdevice::TryFormat);
> > +	if (ret)
> > +		return ret;
> > +
> > +	ret = subdev->setRouting(&routing, V4L2Subdevice::ActiveFormat);
> > +	if (ret)
> > +		return ret;
> 
> Is this a normal way to reset things in v4l2? Say, if you want to reset 
> the fmt on a pad?

There's no explicit reset API, getting the default value using a try
context is the best way I know of. This only works if the try context
isn't modified of course, which is fine here.

> Reviewed-by: Tomi Valkeinen <tomi.valkeinen at ideasonboard.com>

-- 
Regards,

Laurent Pinchart