On Fri, Mar 02, 2018 at 04:48:03PM +0100, Stefan Schake wrote: > On Fri, Mar 2, 2018 at 4:21 PM, Ville Syrjälä > <ville.syrjala@xxxxxxxxxxxxxxx> wrote: > > 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.syrjala@xxxxxxxxxxxxxxx> 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? > > Well since we have no real primary plane we'd have to remove support from > every plane or add elaborate logic to atomic check that detects and rejects > a configuration that has pixels blending from nothing, which presumably is > what triggers the display artifacts. > > >> 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. > > Then to be sure we should always enable the background fill. Maybe Eric can > clarify what the cost for this is, all I have to go on there is the comment > on the register set. Yeah, that sounds like the correct thing to do. -- Ville Syrjälä Intel OTC _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
