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

[Geert Uytterhoeven]

Hi Maxime,

On Tue, Aug 16, 2022 at 3:20 PM Maxime Ripard <maxime@xxxxxxxxxx> wrote:
> On Fri, Aug 12, 2022 at 03:25:18PM +0200, Geert Uytterhoeven wrote:
> > > --- a/drivers/gpu/drm/drm_connector.c
> > > +++ b/drivers/gpu/drm/drm_connector.c
> > > @@ -1649,11 +1650,40 @@ EXPORT_SYMBOL(drm_mode_create_tv_margin_properties);
> > >   * 0 on success or a negative error code on failure.
> > >   */
> > >  int drm_mode_create_tv_properties(struct drm_device *dev,
> > > +                                 unsigned int supported_tv_norms,
> > >                                   unsigned int num_modes,
> > >                                   const char * const modes[])
> > >  {
> > > +       static const struct drm_prop_enum_list tv_norm_values[] = {
> > > +               { __builtin_ffs(DRM_MODE_TV_NORM_NTSC_443) - 1, "NTSC-443" },
> > > +               { __builtin_ffs(DRM_MODE_TV_NORM_NTSC_J) - 1, "NTSC-J" },
> > > +               { __builtin_ffs(DRM_MODE_TV_NORM_NTSC_M) - 1, "NTSC-M" },
> > > +               { __builtin_ffs(DRM_MODE_TV_NORM_PAL_60) - 1, "PAL-60" },
> > > +               { __builtin_ffs(DRM_MODE_TV_NORM_PAL_B) - 1, "PAL-B" },
> > > +               { __builtin_ffs(DRM_MODE_TV_NORM_PAL_D) - 1, "PAL-D" },
> > > +               { __builtin_ffs(DRM_MODE_TV_NORM_PAL_G) - 1, "PAL-G" },
> > > +               { __builtin_ffs(DRM_MODE_TV_NORM_PAL_H) - 1, "PAL-H" },
> > > +               { __builtin_ffs(DRM_MODE_TV_NORM_PAL_I) - 1, "PAL-I" },
> > > +               { __builtin_ffs(DRM_MODE_TV_NORM_PAL_M) - 1, "PAL-M" },
> > > +               { __builtin_ffs(DRM_MODE_TV_NORM_PAL_N) - 1, "PAL-N" },
> > > +               { __builtin_ffs(DRM_MODE_TV_NORM_PAL_NC) - 1, "PAL-Nc" },
> > > +               { __builtin_ffs(DRM_MODE_TV_NORM_SECAM_60) - 1, "SECAM-60" },
> > > +               { __builtin_ffs(DRM_MODE_TV_NORM_SECAM_B) - 1, "SECAM-B" },
> > > +               { __builtin_ffs(DRM_MODE_TV_NORM_SECAM_D) - 1, "SECAM-D" },
> > > +               { __builtin_ffs(DRM_MODE_TV_NORM_SECAM_G) - 1, "SECAM-G" },
> > > +               { __builtin_ffs(DRM_MODE_TV_NORM_SECAM_K) - 1, "SECAM-K" },
> > > +               { __builtin_ffs(DRM_MODE_TV_NORM_SECAM_K1) - 1, "SECAM-K1" },
> > > +               { __builtin_ffs(DRM_MODE_TV_NORM_SECAM_L) - 1, "SECAM-L" },
> >
> > The above are analog standards, with a variable horizontal resolution.
> >
> > > +               { __builtin_ffs(DRM_MODE_TV_NORM_HD480I) - 1, "hd480i" },
> > > +               { __builtin_ffs(DRM_MODE_TV_NORM_HD480P) - 1, "hd480p" },
> > > +               { __builtin_ffs(DRM_MODE_TV_NORM_HD576I) - 1, "hd576i" },
> > > +               { __builtin_ffs(DRM_MODE_TV_NORM_HD576P) - 1, "hd576p" },
> > > +               { __builtin_ffs(DRM_MODE_TV_NORM_HD720P) - 1, "hd720p" },
> > > +               { __builtin_ffs(DRM_MODE_TV_NORM_HD1080I) - 1, "hd1080i" },
> >
> > The above are digital standards, with a fixed resolution.
>
> Are they?
>
> It's not clear to me from looking at nouveau, but I was under the
> impression that they were modes for a component output, so CEA 770.3. I
> don't have the spec though, so I can't check.

Oh right, I forgot about analog HD over component, where you can use
other pixel clocks than in the digital standard.

> > You seem to have missed "hd1080p"?
>
> Nobody is using it. If we ever have a driver that uses it I think we can
> add it.

The PS3 supports 1080p over component
https://manuals.playstation.net/document/en/ps3/current/settings/videooutput.html

> > In addition, "hd720p", "hd080i", and "hd1080p" are available in both 50
> > and 60 (actually 59.94) Hz, while "hd1080p" can also use 24 or 25 Hz.
>
> It looks like nouveau only exposes modes for 480p at 59.94Hz, 576p at
> 50Hz, 720p at 60Hz, 1080i at 30Hz.

PS3 supports both 50 and 60 Hz (same link above).

> > 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"?

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds