From: Mario Limonciello <mario.limoncie...@amd.com>
[Why]
Custom brightness curve works by walking through all data points one
by one. When the brightness value is at either extreme this is a lot
of data points to walk. This is especially noticeable when moving a
brightness slider around how it can lag.
[How]
Bisect the data points to find the closest for interpolation.
Reviewed-by: Alex Hung <alex.h...@amd.com>
Signed-off-by: Mario Limonciello <mario.limoncie...@amd.com>
Signed-off-by: Alex Hung <alex.h...@amd.com>
Tested-by: Dan Wheeler <daniel.whee...@amd.com>
---
.../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 64 +++++++++++--------
1 file changed, 38 insertions(+), 26 deletions(-)
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 12eb1a91a4e9..242f98564261 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -4817,8 +4817,8 @@ static void convert_custom_brightness(const struct
amdgpu_dm_backlight_caps *cap
uint32_t *user_brightness)
{
u32 brightness = scale_input_to_fw(min, max, *user_brightness);
- u8 prev_signal = 0, prev_lum = 0;
- int i = 0;
+ u8 lower_signal, upper_signal, upper_lum, lower_lum, lum;
+ int left, right;
if (amdgpu_dc_debug_mask & DC_DISABLE_CUSTOM_BRIGHTNESS_CURVE)
return;
@@ -4826,32 +4826,44 @@ static void convert_custom_brightness(const struct
amdgpu_dm_backlight_caps *cap
if (!caps->data_points)
return;
- /* choose start to run less interpolation steps */
- if (caps->luminance_data[caps->data_points/2].input_signal > brightness)
- i = caps->data_points/2;
- do {
- u8 signal = caps->luminance_data[i].input_signal;
- u8 lum = caps->luminance_data[i].luminance;
+ left = 0;
+ right = caps->data_points - 1;
+ while (left <= right) {
+ int mid = left + (right - left) / 2;
+ u8 signal = caps->luminance_data[mid].input_signal;
- /*
- * brightness == signal: luminance is percent numerator
- * brightness < signal: interpolate between previous and
current luminance numerator
- * brightness > signal: find next data point
- */
- if (brightness > signal) {
- prev_signal = signal;
- prev_lum = lum;
- i++;
- continue;
+ /* Exact match found */
+ if (signal == brightness) {
+ lum = caps->luminance_data[mid].luminance;
+ goto scale;
}
- if (brightness < signal)
- lum = prev_lum + DIV_ROUND_CLOSEST((lum - prev_lum) *
- (brightness -
prev_signal),
- signal -
prev_signal);
- *user_brightness = scale_fw_to_input(min, max,
- DIV_ROUND_CLOSEST(lum *
brightness, 101));
- return;
- } while (i < caps->data_points);
+
+ if (signal < brightness)
+ left = mid + 1;
+ else
+ right = mid - 1;
+ }
+
+ /* verify bound */
+ if (left >= caps->data_points)
+ left = caps->data_points - 1;
+
+ /* At this point, left > right */
+ lower_signal = caps->luminance_data[right].input_signal;
+ upper_signal = caps->luminance_data[left].input_signal;
+ lower_lum = caps->luminance_data[right].luminance;
+ upper_lum = caps->luminance_data[left].luminance;
+
+ /* interpolate */
+ if (right == left || !lower_lum)
+ lum = upper_lum;
+ else
+ lum = lower_lum + DIV_ROUND_CLOSEST((upper_lum - lower_lum) *
+ (brightness - lower_signal),
+ upper_signal -
lower_signal);
+scale:
+ *user_brightness = scale_fw_to_input(min, max,
+ DIV_ROUND_CLOSEST(lum *
brightness, 101));
}
static u32 convert_brightness_from_user(const struct amdgpu_dm_backlight_caps
*caps,
--
2.43.0
