diff options
| author | Anthony Koo <Anthony.Koo@amd.com> | 2021-01-15 21:45:43 -0500 |
|---|---|---|
| committer | Alex Deucher <alexander.deucher@amd.com> | 2021-02-02 12:09:46 -0500 |
| commit | 4fa6a75128ae8b12cdfe41938d9d2ab301285a22 (patch) | |
| tree | 632a8b9bb608c4a69faa826786e375ba5304b1d1 | |
| parent | b99844e4237ea7766d8d8f39ab727d17ccb9ca55 (diff) | |
drm/amd/display: fix calculation for the pwl backlight curve
[Why]
The PWL backlight curve is used by the firmware to convert between
brightness and linear PWM value.
Driver has a backlight LUT, but the firmware holds a PWL curve and
interpolates between points.
The calculations are incorrect leading to slightly off backlight values
being programmed.
[How]
Fix the PWL backlight curve threshold/offset calculations
Signed-off-by: Anthony Koo <Anthony.Koo@amd.com>
Reviewed-by: Josip Pavic <Josip.Pavic@amd.com>
Acked-by: Anson Jacob <Anson.Jacob@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
| -rw-r--r-- | drivers/gpu/drm/amd/display/modules/power/power_helpers.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/gpu/drm/amd/display/modules/power/power_helpers.c b/drivers/gpu/drm/amd/display/modules/power/power_helpers.c index 3d4c66933f51..6270ecbd2438 100644 --- a/drivers/gpu/drm/amd/display/modules/power/power_helpers.c +++ b/drivers/gpu/drm/amd/display/modules/power/power_helpers.c @@ -266,7 +266,7 @@ static void fill_backlight_transform_table_v_2_2(struct dmcu_iram_parameters par * format U4.10. */ for (i = 1; i+1 < num_entries; i++) { - lut_index = (params.backlight_lut_array_size - 1) * i / (num_entries - 1); + lut_index = DIV_ROUNDUP((i * params.backlight_lut_array_size), num_entries); ASSERT(lut_index < params.backlight_lut_array_size); table->backlight_thresholds[i] = (big_endian) ? |