[PATCH] Revert "drm/amd/display: Fix AMDGPU_MAX_BL_LEVEL value"

Mario Limonciello superm1 at kernel.org
Mon Jul 21 13:43:50 UTC 2025


From: Mario Limonciello <mario.limonciello at amd.com>

This reverts commit 66abb996999de0d440a02583a6e70c2c24deab45.
This broke custom brightness curves but it wasn't obvious because
of other related changes. Custom brightness curves are always
from a 0-255 input signal. The correct fix was to fix the default
value which was done by [1].

Closes: https://gitlab.freedesktop.org/drm/amd/-/issues/4412
Cc: stable at vger.kernel.org
Link: https://lore.kernel.org/amd-gfx/0f094c4b-d2a3-42cd-824c-dc2858a5618d@kernel.org/T/#m69f875a7e69aa22df3370b3e3a9e69f4a61fdaf2
Signed-off-by: Mario Limonciello <mario.limonciello at amd.com>
---
 drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 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 8e1405e9025ba..f3e407f31de11 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -4740,16 +4740,16 @@ static int get_brightness_range(const struct amdgpu_dm_backlight_caps *caps,
 	return 1;
 }
 
-/* Rescale from [min..max] to [0..MAX_BACKLIGHT_LEVEL] */
+/* Rescale from [min..max] to [0..AMDGPU_MAX_BL_LEVEL] */
 static inline u32 scale_input_to_fw(int min, int max, u64 input)
 {
-	return DIV_ROUND_CLOSEST_ULL(input * MAX_BACKLIGHT_LEVEL, max - min);
+	return DIV_ROUND_CLOSEST_ULL(input * AMDGPU_MAX_BL_LEVEL, max - min);
 }
 
-/* Rescale from [0..MAX_BACKLIGHT_LEVEL] to [min..max] */
+/* Rescale from [0..AMDGPU_MAX_BL_LEVEL] to [min..max] */
 static inline u32 scale_fw_to_input(int min, int max, u64 input)
 {
-	return min + DIV_ROUND_CLOSEST_ULL(input * (max - min), MAX_BACKLIGHT_LEVEL);
+	return min + DIV_ROUND_CLOSEST_ULL(input * (max - min), AMDGPU_MAX_BL_LEVEL);
 }
 
 static void convert_custom_brightness(const struct amdgpu_dm_backlight_caps *caps,
@@ -4977,7 +4977,7 @@ amdgpu_dm_register_backlight_device(struct amdgpu_dm_connector *aconnector)
 		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 = props.max_brightness = MAX_BACKLIGHT_LEVEL;
+		props.brightness = props.max_brightness = AMDGPU_MAX_BL_LEVEL;
 
 	if (caps->data_points && !(amdgpu_dc_debug_mask & DC_DISABLE_CUSTOM_BRIGHTNESS_CURVE))
 		drm_info(drm, "Using custom brightness curve\n");
-- 
2.43.0



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