Re: [PATCH v1 05/35] drm/connector: Add TV standard property

[Maxime Ripard]

On Tue, Aug 16, 2022 at 11:42:20AM +0200, Noralf Trønnes wrote:
> 
> 
> Den 16.08.2022 10.26, skrev Maxime Ripard:
> > Hi,
> > 
> > On Mon, Aug 08, 2022 at 02:44:56PM +0200, Noralf Trønnes wrote:
> >> Den 29.07.2022 18.34, skrev Maxime Ripard:
> >>> The TV mode property has been around for a while now to select and get the
> >>> current TV mode output on an analog TV connector.
> >>>
> >>> Despite that property name being generic, its content isn't and has been
> >>> driver-specific which makes it hard to build any generic behaviour on top
> >>> of it, both in kernel and user-space.
> >>>
> >>> Let's create a new bitmask tv norm property, that can contain any of the
> >>> analog TV standards currently supported by kernel drivers. Each driver can
> >>> then pass in a bitmask of the modes it supports.
> >>>
> >>> We'll then be able to phase out the older tv mode property.
> >>>
> >>> Signed-off-by: Maxime Ripard <maxime@xxxxxxxxxx>
> >>>
> >>
> >> Please also update Documentation/gpu/kms-properties.csv
> >>
> >> Requirements for adding a new property is found in
> >> Documentation/gpu/drm-kms.rst
> > 
> > I knew this was going to be raised at some point, so I'm glad it's that
> > early :)
> > 
> > I really don't know what to do there. If we stick by our usual rules,
> > then we can't have any of that work merged.
> > 
> > However, I think the status quo is not really satisfactory either.
> > Indeed, we have a property, that doesn't follow those requirements
> > either, with a driver-specific content, and that stands in the way of
> > fixes and further improvements at both the core framework and driver
> > levels.
> > 
> > So having that new property still seems like a net improvement at the
> > driver, framework and uAPI levels, even if it's not entirely following
> > the requirements we have in place.
> > 
> > Even more so since, realistically, those kind of interfaces will never
> > get any new development on the user-space side of things, it's
> > considered by everyone as legacy.
> > 
> > This also is something we need to support at some point if we want to
> > completely deprecate the fbdev drivers and provide decent alternatives
> > in KMS.
> > 
> > So yeah, strictly speaking, we would not qualify for our requirements
> > there. I still think we have a strong case for an exception though.
>
> Which requirements would that be? The only one I can see is the
> documentation and maybe an IGT test.

This is the one I had in mind
https://dri.freedesktop.org/docs/drm/gpu/drm-uapi.html#open-source-userspace-requirements

I overlooked yours obviously, so I'll update my patches to fix it.

Maxime

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