On Fri, Jun 10, 2016 at 03:08:18PM +0300, Tomi Valkeinen wrote: > On 10/06/16 15:05, Ville Syrjälä wrote: > > >> I'm not sure what's the common way, but tilcdc doesn't support alpha. > >> ARGB works, of course, by ignoring A, but... If an userspace app creates > >> ARGB buffer, does the app expect alpha to work? > > > > I think what we decided a while ago (at least for i915, but would be good > > to use the same convention everywhere) was that ARGB will be assumed to be > > pre-multiplied and will enable blending using 1.0*sc+(1.0-sa)*dc as the > > function. There have been some efforts at defining some new properties to > > control the blend equation, but I guess those got bogged down again. > > Ok, but that's a bit different topic. The question here is, if the HW > doesn't support alpha (no planes, so nothing to blend), should it accept > ARGB or not. What do you mean "no planes"? You have to have a plane if you want to scanout a framebuffer. And even if you have just one plane with alpha blending, it should be blended with the background color (which is black until we get a property to change it). -- Ville Syrjälä Intel OTC _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
