Re: [PATCH] drm/sun4i: Use vi plane as primary

From: Maxime Ripard
Date: Fri Sep 20 2019 - 02:12:18 EST


On Thu, Sep 19, 2019 at 08:15:49PM +0200, Jernej Åkrabec wrote:
> Dne Äetrtek, 19. september 2019 ob 19:17:54 CEST je Maxime Ripard napisal(a):
> > >
> > > Tested on Android.
> > >
> > > Signed-off-by: Roman Stratiienko <roman.stratiienko@xxxxxxxxxxxxxxx>
> >
> > It sounds like a workaround more than an actual fix.
> >
> > If the VI planes can't use the alpha, then we should just stop
> > reporting that format.
> >
> > Jernej, what do you think?
>
> Commit message is misleading. What this commit actually does is moving primary
> plane from first UI plane to bottom most plane, i.e. first VI plane. However, VI
> planes are scarce resource, almost all mixers have only one. I wouldn't set it
> as primary, because it's the only one which provide support for YUV formats.
> That could be used for example by video player for zero-copy rendering.
> Probably most apps wouldn't touch it if it was primary (that's usually
> reserved for window manager, if used).

Yeah, we definitely don't want to use it as primary and prevent the
video display.

> I left few formats with alpha channel exposed by VI planes, just because they
> don't have equivalent format without alpha. But I'm fine with removing them if
> you all agree on that.

If there's no alpha support, then yeah, we shouldn't expose the format
at all, and then we can either add the new formats, or just not expose
them if they are exotic enough.

Maxime

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