From: Mario Limonciello <mario.limoncie...@amd.com>
[Why]
If the first data point for a custom brightness curve is not 0% luminance
then the first few luminance values will be ignored.
[How]
Check signal is below first data point and if so do linear interpolation to
0 instead.
Reviewed-by: Alex Hung <alex.h...@amd.com>
Signed-off-by: Mario Limonciello <mario.limoncie...@amd.com>
Signed-off-by: Ivan Lipski <ivan.lip...@amd.com>
---
drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
index b7b933a33316..2f856ed99b63 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -4821,6 +4821,16 @@ static void convert_custom_brightness(const struct
amdgpu_dm_backlight_caps *cap
if (!caps->data_points)
return;
+ /*
+ * Handle the case where brightness is below the first data point
+ * Interpolate between (0,0) and (first_signal, first_lum)
+ */
+ if (brightness < caps->luminance_data[0].input_signal) {
+ lum = DIV_ROUND_CLOSEST(caps->luminance_data[0].luminance *
brightness,
+ caps->luminance_data[0].input_signal);
+ goto scale;
+ }
+
left = 0;
right = caps->data_points - 1;
while (left <= right) {
--
2.43.0
