From 4b61b8a390511a1864f26cc42bab72881e93468d Mon Sep 17 00:00:00 2001 From: Mario Limonciello Date: Wed, 14 May 2025 16:00:43 -0500 Subject: [PATCH] drm/amd/display: Add debugging message for brightness caps [Why] Default BIOS brightness caps are buried in ACPI. [How] Add extra dynamic debug that can show default brightness caps. Reviewed-by: Alex Hung Signed-off-by: Mario Limonciello Signed-off-by: Wayne Lin Tested-by: Daniel Wheeler Signed-off-by: Alex Deucher --- drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 7 ++++++- 1 file changed, 6 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 1797fa85fac6..588f6afb1447 100644 --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c @@ -4910,6 +4910,7 @@ amdgpu_dm_register_backlight_device(struct amdgpu_dm_connector *aconnector) struct backlight_properties props = { 0 }; struct amdgpu_dm_backlight_caps caps = { 0 }; char bl_name[16]; + int min, max; if (aconnector->bl_idx == -1) return; @@ -4922,11 +4923,15 @@ amdgpu_dm_register_backlight_device(struct amdgpu_dm_connector *aconnector) } amdgpu_acpi_get_backlight_caps(&caps); - if (caps.caps_valid) { + if (caps.caps_valid && get_brightness_range(&caps, &min, &max)) { if (power_supply_is_system_supplied() > 0) props.brightness = caps.ac_level; else props.brightness = caps.dc_level; + /* min is zero, so max needs to be adjusted */ + props.max_brightness = max - min; + drm_dbg(drm, "Backlight caps: min: %d, max: %d, ac %d, dc %d\n", min, max, + caps.ac_level, caps.dc_level); } else props.brightness = AMDGPU_MAX_BL_LEVEL; -- 2.47.2