Re: [PATCH v8 6/9] media: Documentation: Add a note to set all fields in get_mbus_config op

[Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>]

On 17/12/2024 23:54, Sakari Ailus wrote:
> Document that the implementations of the V4L2 sub-device pad operation
> get_mbus_config shall set all fields of the struct to defined values.
> 
> Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
> ---
>   include/media/v4l2-subdev.h | 5 ++++-
>   1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/include/media/v4l2-subdev.h b/include/media/v4l2-subdev.h
> index 2f2200875b03..abcc879fabb2 100644
> --- a/include/media/v4l2-subdev.h
> +++ b/include/media/v4l2-subdev.h
> @@ -822,7 +822,10 @@ struct v4l2_subdev_state {
>    *		     possible configuration from the remote end, likely calling
>    *		     this operation as close as possible to stream on time. The
>    *		     operation shall fail if the pad index it has been called on
> - *		     is not valid or in case of unrecoverable failures.
> + *		     is not valid or in case of unrecoverable failures. The
> + *		     implementations of the get_mbus_config operation shall set
> + *		     all the values of struct v4l2_mbus_config to defined
> + *		     values.

The drivers can't set all fields, as we can add new fields (like you do 
in this series). So I assume this means that the drivers should memset() 
the struct to 0, and only then set the values it wants?

I think we should have a wrapper for get_mbus_config, which would clear 
the struct before calling the op. And the drivers should always use that 
wrapper.

  Tomi