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

[Sakari Ailus <sakari.ailus@linux.intel.com>]

On Fri, Dec 20, 2024 at 03:29:27PM +0200, Tomi Valkeinen wrote:
> 
> 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.

It seems we already have a wrapper actually, one that checks the pad
argument is valid. I'll add the memset().

-- 
Sakari Ailus