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

[Maxime Ripard]

On Wed, Aug 17, 2022 at 10:35:07AM +0200, Geert Uytterhoeven wrote:
> Hi Maxime,
> 
> On Wed, Aug 17, 2022 at 9:47 AM Maxime Ripard <maxime@xxxxxxxxxx> wrote:
> > On Wed, Aug 17, 2022 at 09:31:18AM +0200, Geert Uytterhoeven wrote:
> > > On Tue, Aug 16, 2022 at 5:50 PM Maxime Ripard <maxime@xxxxxxxxxx> wrote:
> > > > On Tue, Aug 16, 2022 at 04:43:44PM +0200, Geert Uytterhoeven wrote:
> > > > > > > > > Either you have to add them here (e.g. "hd720p50" and "hd720p60"), or
> > > > > > > > > handle them through "@<refresh>".  The latter would impact "[PATCH v1
> > > > > > > > > 09/35] drm/modes: Move named modes parsing to a separate function", as
> > > > > > > > > currently a named mode and a refresh rate can't be specified both.
> > > > > > > >
> > > > > > > > I think the former would make more sense. It simplifies a bit the
> > > > > > > > parser, and we're going to use a named mode anyway.
> > > > > > > >
> > > > > > > > > As "[PATCH v1 34/35] drm/modes: Introduce the tv_mode property as a
> > > > > > > > > command-line option" uses a separate "tv_mode" option, and not the main
> > > > > > > > > mode name, I think you want to add them here.
> > > > > > > >
> > > > > > > > It's a separate story I think, we could have a named mode hd720p50,
> > > > > > > > which would be equivalent to 1280x720,tv_mode=hd720p
> > > > > > >
> > > > > > > So where's the field rate in "1280x720,tv_mode=hd720p"?
> > > > > >
> > > > > > Yeah, sorry I meant 1280x720@50,tv_mode=hd720p
> > > > >
> > > > > Above you said "I think the former would make more sense", so that
> > > > > should be "1280x720,tv_mode=hd720p50"?
> > > >
> > > > No, 720p at 50Hz would be either hd720p50 or 1280x720@50,tv_mode=hd720p
> > > > and 60Hz would be hd720p60 or 1280x720@60,tv_mode=hd720p
> > >
> > > I disagree: hd720p50 and hd720p60 are different TV modes.
> >
> > I agree, and I don't see how that command-line doesn't express that?
> 
> Oh, I see what you mean: yes, it expresses that.
> But it is inconsistent with the NTSC/PAL/SECAM/hd{480,576}[ip] modes,
> where the TV mode specifies both number of lines and frame rate.

Only if we're using a named mode, and naming is hard :)

Honestly, I'd be inclined to drop the hd* for now from this series. I
don't have a hardware to test it with, for some we don't even have
drivers that could implement these modes, we don't have a spec to work
from, it looks like a recipe for failure :)

Maxime

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