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| author | Hsiao Chien Sung <shawn.sung@mediatek.com> | 2024-06-20 00:38:45 +0800 |
|---|---|---|
| committer | Chun-Kuang Hu <chunkuang.hu@kernel.org> | 2024-06-20 13:57:35 +0000 |
| commit | 31c0fbf67c8c0bb38d7fb21d404ea3dbd619d99e (patch) | |
| tree | eb378a0a459814f6c1657d93ac68b1fa6edcf785 /tools/perf/scripts/python/Perf-Trace-Util/lib/Perf/Trace/EventClass.py | |
| parent | 8e418bee401b7cfd0bc40d187afea2c6b08b44ec (diff) | |
drm/mediatek: Fix destination alpha error in OVL
The formula of Coverage alpha blending is:
dst.a = dst.a * (0xff - src.a * SCA / 0xff) / 0xff
+ src.a * SCA / 0xff
dst.a: destination alpha
src.a: pixel alpha
SCA : plane alpha
When SCA = 0xff, the formula becomes:
dst.a = dst.a * (0xff - src.a) + src.a
This patch is to set the destination alpha (background) to 0xff:
- When dst.a = 0 (before), dst.a = src.a
- When dst.a = 0xff (after) , dst.a = 0xff * (0xff - src.a) + src.a
According to the fomula above:
- When src.a = 0 , dst.a = 0
- When src.a = 0xff, dst.a = 0xff
This two cases are just still correct. But when src.a is
between 0 and 0xff, the difference starts to appear
Fixes: 616443ca577e ("drm/mediatek: Move cmdq_reg info from struct mtk_ddp_comp to sub driver private data")
Signed-off-by: Hsiao Chien Sung <shawn.sung@mediatek.com>
Link: https://patchwork.kernel.org/project/dri-devel/patch/20240620-igt-v3-5-a9d62d2e2c7e@mediatek.com/
Signed-off-by: Chun-Kuang Hu <chunkuang.hu@kernel.org>
Diffstat (limited to 'tools/perf/scripts/python/Perf-Trace-Util/lib/Perf/Trace/EventClass.py')
0 files changed, 0 insertions, 0 deletions