diff options
| author | Maxime Ripard <maxime.ripard@free-electrons.com> | 2017-06-26 23:51:15 +0300 |
|---|---|---|
| committer | Maxime Ripard <maxime.ripard@free-electrons.com> | 2018-01-29 16:02:42 +0300 |
| commit | 65f7fa3a3fcbdb67940a58ce24516d62aaec12b7 (patch) | |
| tree | 8f3cf4a62a4c44b8731b13e5a045fb0f043f3ffe /drivers/gpu/drm/sun4i/sun4i_layer.c | |
| parent | 47a05f4a68f91c09d89d2a0231b7b8c7ebb808ca (diff) | |
| download | linux-65f7fa3a3fcbdb67940a58ce24516d62aaec12b7.tar.xz | |
drm/sun4i: backend: Check for the number of alpha planes
Due to the way the composition is done in hardware, we can only have a
single alpha-enabled plane active at a time, placed in the second (highest
priority) pipe.
Make sure of that in our atomic_check to not end up in an impossible
scenario.
Reviewed-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Link: https://patchwork.freedesktop.org/patch/msgid/7371f62a1385f2cbe3ed75dfca2e746338eb2286.1516617243.git-series.maxime.ripard@free-electrons.com
Diffstat (limited to 'drivers/gpu/drm/sun4i/sun4i_layer.c')
| -rw-r--r-- | drivers/gpu/drm/sun4i/sun4i_layer.c | 24 |
1 files changed, 2 insertions, 22 deletions
diff --git a/drivers/gpu/drm/sun4i/sun4i_layer.c b/drivers/gpu/drm/sun4i/sun4i_layer.c index fbf25d59cf88..19be798e4fac 100644 --- a/drivers/gpu/drm/sun4i/sun4i_layer.c +++ b/drivers/gpu/drm/sun4i/sun4i_layer.c @@ -201,32 +201,12 @@ struct drm_plane **sun4i_layers_init(struct drm_device *drm, struct sun4i_backend *backend = engine_to_sun4i_backend(engine); int i; - planes = devm_kcalloc(drm->dev, ARRAY_SIZE(sun4i_backend_planes) + 1, + /* We need to have a sentinel at the need, hence the overallocation */ + planes = devm_kcalloc(drm->dev, SUN4I_BACKEND_NUM_LAYERS + 1, sizeof(*planes), GFP_KERNEL); if (!planes) return ERR_PTR(-ENOMEM); - /* - * The hardware is a bit unusual here. - * - * Even though it supports 4 layers, it does the composition - * in two separate steps. - * - * The first one is assigning a layer to one of its two - * pipes. If more that 1 layer is assigned to the same pipe, - * and if pixels overlaps, the pipe will take the pixel from - * the layer with the highest priority. - * - * The second step is the actual alpha blending, that takes - * the two pipes as input, and uses the eventual alpha - * component to do the transparency between the two. - * - * This two steps scenario makes us unable to guarantee a - * robust alpha blending between the 4 layers in all - * situations. So we just expose two layers, one per pipe. On - * SoCs that support it, sprites could fill the need for more - * layers. - */ for (i = 0; i < ARRAY_SIZE(sun4i_backend_planes); i++) { const struct sun4i_plane_desc *plane = &sun4i_backend_planes[i]; struct sun4i_layer *layer; |