[libcamera-devel] [PATCH v2 1/2] libcamera: camera_sensor: Clear camera flips after opening the device

[Kieran Bingham]

Quoting David Plowman (2022-01-13 14:15:57)
> We clear the V4L2_CID_HFLIP and V4L2_CID_VFLIP controls immediately
> after opening the camera device. This means the camera's Bayer format
> and mbus codes will be in the sensor's "native" order, and we document
> this to be the case so that it can be relied upon.
> 
> Clearing the flips is harmless where sensor flips do not affect the
> Bayer order.
> 
> This also fixes a bug in the Raspberry Pi pipeline handler where the
> native Bayer order was being computed wrongly, but the new behaviour
> here will be helpful to other pipeline handlers too. A subsequent
> commit will tidy up the Raspberry Pi pipeline handler in this area as
> it can now be simplified.
> 
> Signed-off-by: David Plowman <david.plowman at raspberrypi.com>
> Fixes: 83a512816189 (pipeline: raspberrypi: Convert the pipeline handler to use media controller)

Fixes: 83a512816189 ("pipeline: raspberrypi: Convert the pipeline handler to use media controller")

Fixes tags usually have the $SUBJECT of the fix in quotes I believe.

It's defined by the kernel at:

https://www.kernel.org/doc/html/v4.17/process/submitting-patches.html#describe-your-changes

I don't think that needs a resubmit by itself though, just highlighting
for awareness, as I'm sure I've seen more fixes tags without quotes on
the list.


Reviewed-by: Kieran Bingham <kieran.bingham at ideasonboard.com>

> ---
>  src/libcamera/camera_sensor.cpp | 16 ++++++++++++++++
>  1 file changed, 16 insertions(+)
> 
> diff --git a/src/libcamera/camera_sensor.cpp b/src/libcamera/camera_sensor.cpp
> index c3999d35..64f7f12c 100644
> --- a/src/libcamera/camera_sensor.cpp
> +++ b/src/libcamera/camera_sensor.cpp
> @@ -107,6 +107,17 @@ int CameraSensor::init()
>         if (ret < 0)
>                 return ret;
>  
> +       /*
> +        * Clear any flips to be sure we get the "native" Bayer order. This is
> +        * harmless for sensors where the flips don't affect the Bayer order.
> +        */
> +       ControlList ctrls(subdev_->controls());
> +       if (subdev_->controls().find(V4L2_CID_HFLIP) != subdev_->controls().end())
> +               ctrls.set(V4L2_CID_HFLIP, 0);
> +       if (subdev_->controls().find(V4L2_CID_VFLIP) != subdev_->controls().end())
> +               ctrls.set(V4L2_CID_VFLIP, 0);
> +       subdev_->setControls(&ctrls);
> +
>         /* Enumerate, sort and cache media bus codes and sizes. */
>         formats_ = subdev_->formats(pad_);
>         if (formats_.empty()) {
> @@ -461,6 +472,11 @@ int CameraSensor::initProperties()
>  /**
>   * \fn CameraSensor::mbusCodes()
>   * \brief Retrieve the media bus codes supported by the camera sensor
> + *
> + * Any Bayer formats are listed using the sensor's native Bayer order,
> + * that is, with the effect of V4L2_CID_HFLIP and V4L2_CID_VFLIP undone
> + * (where these controls exist).
> + *
>   * \return The supported media bus codes sorted in increasing order
>   */
>  
> -- 
> 2.30.2
>