From: Harry Wentland <harry.wentland@xxxxxxx>
The shaper LUT requires a 10-bit value of the delta between
segments. We were using dc_fixpt_clamp_u0d10() to do that
but it doesn't do what we want it to do. It will preserve
10-bit precision after the decimal point, but that's not
quite what we want. We want 14-bit precision and discard
the 4 most-significant bytes.
To do that we'll do dc_fixpt_clamp_u0d14() & 0x3ff instead.
Signed-off-by: Harry Wentland <harry.wentland@xxxxxxx>
---
.../gpu/drm/amd/display/dc/dcn10/dcn10_cm_common.c | 14 +++++++++++---
1 file changed, 11 insertions(+), 3 deletions(-)
diff --git a/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_cm_common.c b/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_cm_common.c
index f27413e94280..efa6cee649d0 100644
--- a/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_cm_common.c
+++ b/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_cm_common.c
@@ -539,10 +539,18 @@ bool cm_helper_translate_curve_to_hw_format(
rgb->delta_green = dc_fixpt_sub(rgb_plus_1->green, rgb->green);
rgb->delta_blue = dc_fixpt_sub(rgb_plus_1->blue, rgb->blue);
+
if (fixpoint == true) {
- rgb->delta_red_reg = dc_fixpt_clamp_u0d10(rgb->delta_red);
- rgb->delta_green_reg = dc_fixpt_clamp_u0d10(rgb->delta_green);
- rgb->delta_blue_reg = dc_fixpt_clamp_u0d10(rgb->delta_blue);
+ uint32_t red_clamp = dc_fixpt_clamp_u0d14(rgb->delta_red);
+ uint32_t green_clamp = dc_fixpt_clamp_u0d14(rgb->delta_green);
+ uint32_t blue_clamp = dc_fixpt_clamp_u0d14(rgb->delta_blue);
+
+ if (red_clamp >> 10 || green_clamp >> 10 || blue_clamp >> 10)
+ DC_LOG_WARNING("Losing delta precision while programming shaper LUT.");
+
+ rgb->delta_red_reg = red_clamp & 0x3ff;
+ rgb->delta_green_reg = green_clamp & 0x3ff;
+ rgb->delta_blue_reg = blue_clamp & 0x3ff;
rgb->red_reg = dc_fixpt_clamp_u0d14(rgb->red);
rgb->green_reg = dc_fixpt_clamp_u0d14(rgb->green);
rgb->blue_reg = dc_fixpt_clamp_u0d14(rgb->blue);
--
2.39.2
