On Fri, Mar 02, 2018 at 04:06:58PM +0100, Stefan Schake wrote: > Hey Ville, > > On Fri, Mar 2, 2018 at 3:43 PM, Ville Syrjälä > <ville.syrj...@linux.intel.com> wrote: > > On Fri, Mar 02, 2018 at 04:39:22PM +0200, Ville Syrjälä wrote: > >> If you want the plane to always be opaque you shouldn't expose any > >> formats with alpha. > >> > >> Also what happens if one disables the primary plane? Or does the driver > >> not allow that? > > > > Or just makes the plane not cover the entire screen? > > We've exposed alpha formats in the past so disabling that now would break > userspace, certainly Android that chooses alpha-everything.
So it refuses to even run on hardware that can't do per-pixel alpha on the primary plane? > The VC4 HVS > has no fixed planes so I'll acknowledge that the concept of a primary plane > is somewhat dubious and userspace could disable it or make it not cover the > entire screen, making this ineffective. > > But then ultimately there doesn't seem to be a standard for what the display > is supposed to be if you have transparent pixels with no plane to blend to > below. The standard is black. IMO it's a driver bug if it fails to do that. > This helps in the common case, the belts&braces fix would be to > enable the VC4 HVS background color fill incurring a fixed overhead that > in most cases is wasted because the composition ends up being opaque. > > Thanks, > Stefan -- Ville Syrjälä Intel OTC _______________________________________________ dri-devel mailing list firstname.lastname@example.org https://lists.freedesktop.org/mailman/listinfo/dri-devel