drm/radeon: Bypass hw lut's for > 8 bpc framebuffer scanout.
The hardware lut's only have 256 slots for indexing by a
8 bpc framebuffer. In 10 bpc scanout modes, framebuffer
color values would get truncated to their 8 msb's,
thereby losing the extra precision afforded by a 10 bpc
framebuffer.
To retain full precision, bypass the hw lut in 10 bpc
scanout mode.
Signed-off-by: Mario Kleiner <mario.kleiner.de@gmail.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
diff --git a/drivers/gpu/drm/radeon/evergreen_reg.h b/drivers/gpu/drm/radeon/evergreen_reg.h
index a0f63ff..333d143 100644
--- a/drivers/gpu/drm/radeon/evergreen_reg.h
+++ b/drivers/gpu/drm/radeon/evergreen_reg.h
@@ -116,6 +116,8 @@
# define EVERGREEN_GRPH_ARRAY_LINEAR_ALIGNED 1
# define EVERGREEN_GRPH_ARRAY_1D_TILED_THIN1 2
# define EVERGREEN_GRPH_ARRAY_2D_TILED_THIN1 4
+#define EVERGREEN_GRPH_LUT_10BIT_BYPASS_CONTROL 0x6808
+# define EVERGREEN_LUT_10BIT_BYPASS_EN (1 << 8)
#define EVERGREEN_GRPH_SWAP_CONTROL 0x680c
# define EVERGREEN_GRPH_ENDIAN_SWAP(x) (((x) & 0x3) << 0)
# define EVERGREEN_GRPH_ENDIAN_NONE 0