Re: [PATCH 8/9] drm/i915: Don't populate plane->plane for cursors and sprites

Ville Syrjälä
2016-12-19T18:55:47Z

On Mon, Dec 19, 2016 at 10:24:15AM -0800, Matt Roper wrote:
> On Thu, Dec 15, 2016 at 09:59:51PM +0200, Ville Syrjälä wrote:
> > On Thu, Dec 15, 2016 at 05:50:02PM -0200, Paulo Zanoni wrote:
> > > Em Qui, 2016-12-15 às 21:11 +0200, Ville Syrjälä escreveu:
> > > > On Thu, Dec 15, 2016 at 05:05:05PM -0200, Paulo Zanoni wrote:
> > > > >
> > > > > Em Ter, 2016-11-22 às 18:02 +0200, ville.syrjala@linux.intel.com
> > > > > escreveu:
> > > > > >
> > > > > > From: Ville Syrjälä <ville.syrjala@linux.intel.com>
> > > > > >
> > > > > > With plane->plane now purely reserved for the primary planes,
> > > > > > let's
> > > > > > not even populate it for cursors and sprites. Let's switch the
> > > > > > type
> > > > > > to enum plane as well since it's no longer being abused for
> > > > > > anything
> > > > > > else.
> > > > >
> > > > > Since it's a primary plane thing, I think it makes more sense to
> > > > > just
> > > > > leave it at struct intel_crtc instead of having a field that's
> > > > > unused
> > > > > and doesn't make sense in some cases.
> > > >
> > > > Primary plane aren't really primary planes on old platforms though.
> > > > That's just a software concept that has no bearing on the hardware.
> > >
> > > Please explain more since that's not my understanding. I just opened
> > > the gen 2 and 3 spec docs and they do contain tons of "primary plane"
> > > references. I know that the hardware is a little more flexible there,
> >
> > Yep. Planes can be moved to any pipe in general.
> >
> > > but as far as I understand we don't even implement that.
> >
> > Not at the moment. But I have plans...
>
> I'm not even sure where to find bspecs for the really old
> platforms...how flexible were those primary planes? Can we drive both
> "primary" planes at the same time on a single CRTC if we're not using
> the second pipe?

There are three "primary" planes, two cursors, and one video overlay.
Any one can be assigned to either pipe more or less freely (some
restrctions do apply). The planes aren't uniform (not even the
"primary" planes) and instead have different capabilities between them.

--
Ville Syrjälä
Intel OTC