On Mon, Apr 23, 2018 at 04:39:54PM +0200, Maarten Lankhorst wrote: > Op 23-04-18 om 16:30 schreef Ville Syrjälä: > > On Mon, Apr 23, 2018 at 12:49:22PM +0200, Maarten Lankhorst wrote: > >> The rounding can cause a perfectly normal 16x16 src to full-screen > >> dst to be rounded down, even without clipping involved. Because of > >> this we should just remove the adjustment, as no other driver or plane > >> does it. > >> > >> Signed-off-by: Maarten Lankhorst <maarten.lankhorst@xxxxxxxxxxxxxxx> > >> --- > >> drivers/gpu/drm/i915/intel_sprite.c | 5 ----- > >> 1 file changed, 5 deletions(-) > >> > >> diff --git a/drivers/gpu/drm/i915/intel_sprite.c b/drivers/gpu/drm/i915/intel_sprite.c > >> index a1d048af0261..203ca8b362a5 100644 > >> --- a/drivers/gpu/drm/i915/intel_sprite.c > >> +++ b/drivers/gpu/drm/i915/intel_sprite.c > >> @@ -996,11 +996,6 @@ intel_check_sprite_plane(struct intel_plane *plane, > >> return vscale; > >> } > >> > >> - /* Make the source viewport size an exact multiple of the scaling factors. */ > >> - drm_rect_adjust_size(src, > >> - drm_rect_width(dst) * hscale - drm_rect_width(src), > >> - drm_rect_height(dst) * vscale - drm_rect_height(src)); > >> - > > This makes the scaling factor checks a slightly incorrect. Ie. we might > > exceed the max h/vscale a bit without realizing it. It's a shame the > > hardware doesn't let us actually program the scaling factors/increments > > and starting phases anymore :( Also we don't actually know how the > > hardware calculates that stuff (assuming it has such things internally), > > so I'm not actually sure how we should be checking the max limit so > > that we actually check what the hardware will use. > > > > Without a more detailed study of the hardware behaviour I'm thinking > > we should perhaps just check the final src vs. dst coordinates like so: > > if (src > dst*max) > > fail; > > as that would avoid the precision issues with the .16 scaling factors. > > > > Another option could be to round h/vscale up. That should guarantee > > that we never exceed the max. > Could we take a pessimistic view for both sides? Round up if scaling > 1, round down when scaling < 1? > That way we should never be afraid of any limits.. That does sound like a decent idea to me. At least I can't immediately think why it wouldn't work out. -- Ville Syrjälä Intel _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
