On Tue, Aug 16, 2022 at 11:42:20AM +0200, Noralf Trønnes wrote:

Den 16.08.2022 10.26, skrev Maxime Ripard:

quoted

Hi,

On Mon, Aug 08, 2022 at 02:44:56PM +0200, Noralf Trønnes wrote:

quoted

Den 29.07.2022 18.34, skrev Maxime Ripard:

quoted

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 <redacted>

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