On Fri, Jun 5, 2026 at 10:44 AM Doug Anderson <[email protected]> wrote:
>
> Hi,
>
> On Fri, Jun 5, 2026 at 8:28 AM Rob Herring <[email protected]> wrote:
> >
> > > > --- 
> > > > a/Documentation/devicetree/bindings/display/panel/samsung,atna33xc20.yaml
> > > > +++ 
> > > > b/Documentation/devicetree/bindings/display/panel/samsung,atna33xc20.yaml
> > > > @@ -25,6 +25,8 @@ properties:
> > > >                - samsung,atna40ct06
> > > >                # Samsung 14" WQXGA+ (2880x1800 pixels) eDP AMOLED panel
> > > >                - samsung,atna40cu11
> > > > +              # Samsung 14" WQXGA+ (2880x1800 pixels) eDP AMOLED panel
> > > > +              - samsung,atna40hq08
> > >
> > > Sure. I'll repeat the same comment I made the last time someone landed
> > > a change to this file [1] in the hopes that maybe someone will post a
> > > patch one day:
> > >
> > > <repeat>
> > > Given how many of these we're up to now, I'm starting to wonder if we
> > > should come up with a generic compatible like we did with "edp-panel"
> > > and then we can stop having to merge CLs like this. All of these
> > > Samsung OLED eDP panels have the same power up sequence and once we do
> > > that then we can read them via EDID or via DP AUX bus to identify
> > > which specific panel we have and if they need additional tweaking,
> > > just like we do with "edp-panel". Do DT folks have any opinion about
> > > that? Coming up with a name would be a pain since I wouldn't want to
> > > assert that all future Samsung OLED eDP panels will have the same
> > > powerup sequence. Maybe "samsung,amoled-edp-panel-v1" even though that
> > > sounds terrible and there's no known need for a "-v2"?
> > > </repeat>
> >
> > If things are the same, then perhaps there should be a fallback
> > compatible. Or just reuse an existing compatible.
>
> Right, there already is a fallback comparible. This patch is just
> adding a string to the enum that has the fallback compatible
> "samsung,atna33xc20". So someone using this new panel will use:
>
> compatible = "samsung,atna40hq08", "samsung,atna33xc20"
>
> My point was that listing specific panel isn't really valuable here.
> Though the "samsung" power sequence isn't completely compatible with
> the generic "eDP panel" power sequence (which is why they have
> separate drivers), just like generic "eDP panel"s we can query the
> panel ID if there are any per-panel quirks.

Unless the quirk is how to power on/off the panel...

> So the question is: should we stop adding specific panels and just
> always list "samsung,atna33xc20" for all Samsung panels with a
> compatible power sequence, is it worth it to add a more generic name,
> or should we really keep listing all these individual panels for no
> real gain.
>
>
> > I can in no way
> > prevent someone from using 'foo-panel' in their DT when the h/w is
> > actually a foobar panel if the differences are transparent to s/w. (But
> > I will reject a quirk property later on when foobar turns out to be
> > different than foo.)
>
> It's more a question of what guidance we tell people. Here, Konrad is
> trying to do "the right thing" by listing his specific panel and then
> using the fallback. I'm saying "listing the specific panel isn't
> gaining you anything" and I'd rather not have to review / apply these
> pointless additions to the bindings.

I think the guidance is clear. Overall, doing something special here
because Samsung panels are special just muddies what the right thing
is for everyone else.

> ...but I can imagine people will be upset if I tell them to list
> "samsung,atna33xc20" for all compatible Samsung AMOLED panels. It
> would be nicer to come up with some sort of generic name?

Well yes, people have a hard time using compatible strings that don't
sound generic. That's too bad for them.

Rob

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