From 68f3c044f37d9f50d67417fa8018d9cf16423458 Mon Sep 17 00:00:00 2001 From: Mario Limonciello Date: Sun, 24 Aug 2025 15:20:58 -0500 Subject: [PATCH] drm/amd/display: Indicate when custom brightness curves are in use [Why] There is a `scale` sysfs attribute that can be used to indicate when non-linear brightness scaling is in use. As Custom brightness curves work by linear interpolation of points the scale is no longer linear. [How] Indicate non-linear scaling when custom brightness curves in use and linear scaling otherwise. Reviewed-by: Alex Hung Signed-off-by: Mario Limonciello Signed-off-by: Wayne Lin Tested-by: Dan Wheeler Signed-off-by: Alex Deucher --- drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) 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 dc4d04a8ce6b8..8d13212ff4abc 100644 --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c @@ -5060,8 +5060,11 @@ amdgpu_dm_register_backlight_device(struct amdgpu_dm_connector *aconnector) } else props.brightness = props.max_brightness = MAX_BACKLIGHT_LEVEL; - if (caps->data_points && !(amdgpu_dc_debug_mask & DC_DISABLE_CUSTOM_BRIGHTNESS_CURVE)) + if (caps->data_points && !(amdgpu_dc_debug_mask & DC_DISABLE_CUSTOM_BRIGHTNESS_CURVE)) { drm_info(drm, "Using custom brightness curve\n"); + props.scale = BACKLIGHT_SCALE_NON_LINEAR; + } else + props.scale = BACKLIGHT_SCALE_LINEAR; props.type = BACKLIGHT_RAW; snprintf(bl_name, sizeof(bl_name), "amdgpu_bl%d", -- 2.47.3