[PATCH v2 1/4] dt-bindings: display: panel: samsung,atna33xc20: Document ATNA45AF01

[Doug Anderson]

Hi,

On Wed, Jul 17, 2024 at 11:19 PM Krzysztof Kozlowski <krzk at kernel.org> wrote:
>
> On 18/07/2024 02:21, Doug Anderson wrote:
> > Conor (and/or) Krzysztof and Rob,
> >
> > On Mon, Jul 15, 2024 at 8:31 AM Conor Dooley <conor at kernel.org> wrote:
> >>
> >> On Mon, Jul 15, 2024 at 02:15:37PM +0200, Stephan Gerhold wrote:
> >>> The Samsung ATNA45AF01 panel is an AMOLED eDP panel that has backlight
> >>> control over the DP AUX channel. While it works almost correctly with the
> >>> generic "edp-panel" compatible, the backlight needs special handling to
> >>> work correctly. It is similar to the existing ATNA33XC20 panel, just with
> >>> a larger resolution and size.
> >>>
> >>> Add a new "samsung,atna45af01" compatible to describe this panel in the DT.
> >>> Use the existing "samsung,atna33xc20" as fallback compatible since existing
> >>> drivers should work as-is, given that resolution and size are discoverable
> >>> through the eDP link.
> >>>
> >>> Signed-off-by: Stephan Gerhold <stephan.gerhold at linaro.org>
> >>
> >> Acked-by: Conor Dooley <conor.dooley at microchip.com>
> >
> > Can you comment on whether you would consider this bindings a "Fix"
> > since it's a dependency for later patches in this series (which are
> > "Fix"es) to pass dtbs_check? See:
> >
> > https://lore.kernel.org/r/4bca316a-2334-425b-87a6-e1bb241d26b5@linaro.org
>
> The patch itself is not a fix, for sure, but it might be a dependency of
> a fix (which you wrote above), thus could be pulled to stable as a
> dependency.
>
> I do not care about dtbs_check warnings in stable kernels, mostly
> because dtbs_check warnings depend heavily on dtschema and dtschema
> follows mainline kernel. Basically if you had warnings-free v6.8 but try
> to run dtbs_check now with latest dtschema, your results will differ.
>
> At some point in the future, I could imagine "no new dtbs_check warnings
> in stable kernels" requirement or at least preference, but so far I
> don't think there is any benefit.

In this case it's not about whether it makes it to the stable kernel
but about which main kernel it goes through.

If we land the bindings in drm-misc-next right now then it'll be a
long time before it makes it into Linus's tree because of the way that
drm-misc-next merges. It will make it to Linus's tree at 6.12. You can
see the drm-misc merging strategy at:

https://drm.pages.freedesktop.org/maintainer-tools/drm-misc.html

If we land the dts change (a fix) through the Qualcomm tree as a fix
then it should target 6.11.

This means that the 6.11 tree will have a dtbs_check error because it
has the dts change (a fix) but not the bindings change (not a fix).

One way to resolve this would be to treat this bindings as a "fix" and
land it through "drm-misc-fixes". That would make the bindings and
device tree change meet up in Linux 6.11.

Did I get that all correct?

-Doug