[libcamera-devel] your mail

[Laurent Pinchart]

Hi Jacopo,

On Wed, Aug 05, 2020 at 12:57:17PM +0200, Jacopo Mondi wrote:
> Subject: [PATCH 0/4] media: docs: Document pixel array properties
> 
> Hans' patch "[PATCH] imx219: selection compliance fixes" sparkled a discussion
> on how the V4L2 selection targets have to be used in order to access an
> image sensor pixel array properties.
> 
> The discussion shown how much under-specified that part was, so this is
> an attempt to provide a bit documentation for this.
> 
> My feeling is that we're hijacking the existing targets for this use case
> and we should probably define new ones, considering how few users we have in
> mainline of them at the moment.

Do you mean you think we should create new targets instead of reusing
the existing ones as you do in this series ? I don't see anything really
wrong in reusing the existing targets, provided we document them
properly, and it's not too much of a hack (that is, the documented
purpose reasonably matches the target name), but maybe I'm missing the
issue.

> On top Hans' patch with reworded commit message and minor updates.
> 
> For reference, we're using the V4L2 selection targets in libcamera to retrieve
> the sensor pixel array properties to be reported to applications for
> calibration purposes. The currently defined pixel properties for libcamera
> are available here:
> https://git.linuxtv.org/libcamera.git/tree/src/libcamera/property_ids.yaml#n390
> 
> Thanks
>    j
> 
> Hans Verkuil (1):
>   media: i2c: imx219: Selection compliance fixes
> 
> Jacopo Mondi (3):
>   media: docs: Describe pixel array properties
>   media: docs: Describe targets for sensor properties
>   media: docs: USe SUBDEV_G_SELECTION for sensor properties
> 
>  .../userspace-api/media/v4l/dev-subdev.rst    | 85 +++++++++++++++++++
>  .../media/v4l/v4l2-selection-targets.rst      | 49 +++++++++++
>  .../media/v4l/vidioc-subdev-g-selection.rst   |  4 +
>  drivers/media/i2c/imx219.c                    | 17 ++--
>  4 files changed, 147 insertions(+), 8 deletions(-)

-- 
Regards,

Laurent Pinchart