Re: [PATCH v7 00/24] media: i2c: add Maxim GMSL2/3 serializer and deserializer drivers

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

Hi Cosmin,

On Wed, Sep 10, 2025 at 01:48:29PM +0300, Cosmin Tanislav wrote:
> 
> 
> On 9/10/25 9:52 AM, Sakari Ailus wrote:
> > Hi Cosmin,
> > 
> > On Thu, Sep 04, 2025 at 10:52:09AM +0300, Cosmin Tanislav wrote:
> > > Hi Sakari.
> > > 
> > > I recently left Analog Devices but I will continue to try upstreaming
> > > this driver. After the upstreaming is done we can switch the
> > > maintainer status to someone else.
> > 
> > Ack, thank you.
> > 
> > > 
> > > Here's the output for the commands you asked, provided by my
> > > ex-coworker. It's for MAX96716 + 2xMAX96717 + 2x IMX219.
> > > 
> > > Do we need to fix anything based on the compliance tests?
> > 
> > Looking at the errors, it looks like some fixing is needed, possibly also
> > on v4l2-compliance side.
> > 
> 
> I'll take a closer look at the failures whenever I get the time.
> 
> > Regarding GMSL, are the image width, height or mbus code used for anything
> > by the serialiser or deserialiser drivers?
> > 
> 
> No, not really. All the information needed by the GMSL drivers is
> provided through get_frame_desc() ops, and there's no fallback for the
> data type, so the stream format is not involved at all, but as far as I
> remember it's necessary to be set properly for the media pipeline to
> pass validation.

In earlier iterations of multi-stream support we've had link validation dig
this information up from the closest sub-device that supported get_fmt pad
op but that also made the assumption there would be no stream branching
taking place, which is not the case anymore.

I guess the most simple way to address this indeed would be to add the
formats to the streams, even if the driver doesn't need them. Also for
backwards compatiblity related reasons they are probably necessary -- the
older max9671* drivers did support them, too.

This would also address (most of?) the v4l2-compliance issues.

-- 
Kind regards,

Sakari Ailus