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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 710edc70e37e..b60a763f3f95 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -2881,51 +2881,50 @@ static int set_backlight_via_aux(struct dc_link *link, uint32_t brightness)
return rc ? 0 : 1;
}
-static u32 convert_brightness(const struct amdgpu_dm_backlight_caps *caps,
- const uint32_t user_brightness)
+static int get_brightness_range(const struct amdgpu_dm_backlight_caps *caps,
+ unsigned *min, unsigned *max)
{
- u32 min, max, conversion_pace;
- u32 brightness = user_brightness;
-
if (!caps)
- goto out;
+ return 0;
- if (!caps->aux_support) {
- max = caps->max_input_signal;
- min = caps->min_input_signal;
- /*
- * The brightness input is in the range 0-255
- * It needs to be rescaled to be between the
- * requested min and max input signal
- * It also needs to be scaled up by 0x101 to
- * match the DC interface which has a range of
- * 0 to 0xffff
- */
- conversion_pace = 0x101;
- brightness =
- user_brightness
- * conversion_pace
- * (max - min)
- / AMDGPU_MAX_BL_LEVEL
- + min * conversion_pace;
+ if (caps->aux_support) {
+ // Firmware limits are in nits, DC API wants millinits.
+ *max = 1000 * caps->aux_max_input_signal;
+ *min = 1000 * caps->aux_min_input_signal;
} else {
- /* TODO
- * We are doing a linear interpolation here, which is OK but
- * does not provide the optimal result. We probably want
- * something close to the Perceptual Quantizer (PQ) curve.
- */
- max = caps->aux_max_input_signal;
- min = caps->aux_min_input_signal;
-
- brightness = (AMDGPU_MAX_BL_LEVEL - user_brightness) * min
- + user_brightness * max;
- // Multiple the value by 1000 since we use millinits
- brightness *= 1000;
- brightness = DIV_ROUND_CLOSEST(brightness, AMDGPU_MAX_BL_LEVEL);
+ // Firmware limits are 8-bit, PWM control is 16-bit.
+ *max = 0x101 * caps->max_input_signal;
+ *min = 0x101 * caps->min_input_signal;
}
+ return 1;
+}
-out:
- return brightness;
+static u32 convert_brightness_from_user(const struct amdgpu_dm_backlight_caps *caps,
+ uint32_t brightness)
+{
+ unsigned min, max;
+
+ if (!get_brightness_range(caps, &min, &max))
+ return brightness;
+
+ // Rescale 0..255 to min..max
+ return min + DIV_ROUND_CLOSEST((max - min) * brightness,
+ AMDGPU_MAX_BL_LEVEL);
+}
+
+static u32 convert_brightness_to_user(const struct amdgpu_dm_backlight_caps *caps,
+ uint32_t brightness)
+{
+ unsigned min, max;
+
+ if (!get_brightness_range(caps, &min, &max))
+ return brightness;
+
+ if (brightness < min)
+ return 0;
+ // Rescale min..max to 0..255
+ return DIV_ROUND_CLOSEST(AMDGPU_MAX_BL_LEVEL * (brightness - min),
+ max - min);
}
static int amdgpu_dm_backlight_update_status(struct backlight_device *bd)
@@ -2941,7 +2940,7 @@ static int amdgpu_dm_backlight_update_status(struct backlight_device *bd)
link = (struct dc_link *)dm->backlight_link;
- brightness = convert_brightness(&caps, bd->props.brightness);
+ brightness = convert_brightness_from_user(&caps, bd->props.brightness);
// Change brightness based on AUX property
if (caps.aux_support)
return set_backlight_via_aux(link, brightness);
@@ -2958,7 +2957,7 @@ static int amdgpu_dm_backlight_get_brightness(struct backlight_device *bd)
if (ret == DC_ERROR_UNEXPECTED)
return bd->props.brightness;
- return ret;
+ return convert_brightness_to_user(&dm->backlight_caps, ret);
}
static const struct backlight_ops amdgpu_dm_backlight_ops = {
base-commit: bcf876870b95592b52519ed4aafcf9d95999bc9c
|