From mboxrd@z Thu Jan 1 00:00:00 1970 From: julian.calaby@gmail.com (Julian Calaby) Date: Tue, 17 Jul 2018 22:41:20 +1000 Subject: [linux-sunxi] [PATCH 2/2] drm/sun4i: sun4i: Introduce a quirk for lowest plane alpha support In-Reply-To: <20180717085230.17472-2-paul.kocialkowski@bootlin.com> References: <20180717085230.17472-1-paul.kocialkowski@bootlin.com> <20180717085230.17472-2-paul.kocialkowski@bootlin.com> Message-ID: To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Hi Paul, On Tue, Jul 17, 2018 at 6:53 PM Paul Kocialkowski wrote: > > Not all sunxi platforms with the first version of the Display Engine > support an alpha component on the plane with the lowest z position > (as in: lowest z-pos), that gets blended with the background color. > > In particular, the A13 is known to have this limitation. However, it was > recently discovered that the A20 and A33 are capable of having alpha on > their lowest plane. > > Thus, this introduces a specific quirk to indicate such support, > per-platform. Since this was not tested on sun4i and sun6i platforms, a > conservative approach is kept and this feature is not supported. > > Signed-off-by: Paul Kocialkowski > --- > drivers/gpu/drm/sun4i/sun4i_backend.c | 10 ++++++++-- > 1 file changed, 8 insertions(+), 2 deletions(-) > > diff --git a/drivers/gpu/drm/sun4i/sun4i_backend.c b/drivers/gpu/drm/sun4i/sun4i_backend.c > index a3cc398d4d80..cdc4a8a91ea2 100644 > --- a/drivers/gpu/drm/sun4i/sun4i_backend.c > +++ b/drivers/gpu/drm/sun4i/sun4i_backend.c > @@ -584,8 +587,9 @@ static int sun4i_backend_atomic_check(struct sunxi_engine *engine, > } > > /* We can't have an alpha plane at the lowest position */ > - if (plane_states[0]->fb->format->has_alpha || > - (plane_states[0]->alpha != DRM_BLEND_ALPHA_OPAQUE)) > + if ((plane_states[0]->fb->format->has_alpha || > + (plane_states[0]->alpha != DRM_BLEND_ALPHA_OPAQUE)) && > + !backend->quirks->supports_lowest_plane_alpha) >>From a readability perspective, it'd be fractionally nicer if the quirk check was before the alpha checks. Thanks, -- Julian Calaby Email: julian.calaby at gmail.com Profile: http://www.google.com/profiles/julian.calaby/