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

[Naushir Patuck]

Hi David,

Thank you for your patch.

On Thu, 13 Jan 2022 at 14:16, David Plowman <david.plowman at raspberrypi.com>
wrote:

> 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)
>

Reviewed-by: Naushir Patuck <naush at raspberrypi.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
>
>
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