[libcamera-devel] [PATCH] libcamera: camera_sensor: Cache pixel rate

[Paul Elder]

Hi Andrei,

On Fri, Jan 19, 2024 at 02:36:27PM +0300, Andrei Konovalov wrote:
> Hi Paul,
> 
> It doesn't look like it will always work, as there is at least one sensor/driver
> for which the pixel rate depends on the mode:

Ah indeed that does seem to be the case.

Thanks for catching it.


Paul

> 
> https://github.com/raspberrypi/linux/blob/rpi-6.1.y/drivers/media/i2c/imx708.c#L46
> 
> https://github.com/raspberrypi/linux/blob/rpi-6.1.y/drivers/media/i2c/imx708.c#L692
> https://github.com/raspberrypi/linux/blob/rpi-6.1.y/drivers/media/i2c/imx708.c#L715
> https://github.com/raspberrypi/linux/blob/rpi-6.1.y/drivers/media/i2c/imx708.c#L738
> https://github.com/raspberrypi/linux/blob/rpi-6.1.y/drivers/media/i2c/imx708.c#L738
> 
> 
> Thanks,
> Andrei
> 
> On 19.01.2024 14:07, Paul Elder via libcamera-devel wrote:
> > Cache the pixel rate at initialization time instead of fetching it from
> > the v4l2 subdev every time it's needed.
> > 
> > Signed-off-by: Paul Elder <paul.elder at ideasonboard.com>
> > ---
> >   include/libcamera/internal/camera_sensor.h | 2 ++
> >   src/libcamera/camera_sensor.cpp            | 5 ++++-
> >   2 files changed, 6 insertions(+), 1 deletion(-)
> > 
> > diff --git a/include/libcamera/internal/camera_sensor.h b/include/libcamera/internal/camera_sensor.h
> > index 60a8b106d..da3bf12b3 100644
> > --- a/include/libcamera/internal/camera_sensor.h
> > +++ b/include/libcamera/internal/camera_sensor.h
> > @@ -105,6 +105,8 @@ private:
> >   	std::string model_;
> >   	std::string id_;
> > +	uint64_t pixelRate_;
> > +
> >   	V4L2Subdevice::Formats formats_;
> >   	std::vector<unsigned int> mbusCodes_;
> >   	std::vector<Size> sizes_;
> > diff --git a/src/libcamera/camera_sensor.cpp b/src/libcamera/camera_sensor.cpp
> > index 0ef78d9c8..33fdb4c8e 100644
> > --- a/src/libcamera/camera_sensor.cpp
> > +++ b/src/libcamera/camera_sensor.cpp
> > @@ -515,6 +515,9 @@ int CameraSensor::initProperties()
> >   		properties_.set(properties::draft::ColorFilterArrangement, cfa);
> >   	}
> > +	ControlList ctrls = subdev_->getControls({ V4L2_CID_PIXEL_RATE });
> > +	pixelRate_ = ctrls.get(V4L2_CID_PIXEL_RATE).get<int64_t>();
> > +
> >   	return 0;
> >   }
> > @@ -1080,7 +1083,7 @@ int CameraSensor::sensorInfo(IPACameraSensorInfo *info) const
> >   		return -EINVAL;
> >   	}
> > -	info->pixelRate = ctrls.get(V4L2_CID_PIXEL_RATE).get<int64_t>();
> > +	info->pixelRate = pixelRate_;
> >   	const ControlInfo hblank = ctrls.infoMap()->at(V4L2_CID_HBLANK);
> >   	info->minLineLength = info->outputSize.width + hblank.min().get<int32_t>();