drm/amd/display: Allow backlight to go below `AMDGPU_DM_DEFAULT_MIN_BACKLIGHT`

From Mario Limonciello
a94ec40b940599b06fad2c9b7533e4b10bc6645c in linux-6.6.y/6.6.55
87d749a6aab73d8069d0345afaa98297816cb220 in mainline linux

diff --git a/sys/dev/pci/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/sys/dev/pci/drm/amd/display/amdgpu_dm/amdgpu_dm.c
index 70e743b..4d80c46 100644 (file)
--- a/sys/dev/pci/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/sys/dev/pci/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -4068,7 +4068,7 @@ static void amdgpu_dm_update_backlight_caps(struct amdgpu_display_manager *dm,
                int spread = caps.max_input_signal - caps.min_input_signal;
 
                if (caps.max_input_signal > AMDGPU_DM_DEFAULT_MAX_BACKLIGHT ||
-                   caps.min_input_signal < AMDGPU_DM_DEFAULT_MIN_BACKLIGHT ||
+                   caps.min_input_signal < 0 ||
                    spread > AMDGPU_DM_DEFAULT_MAX_BACKLIGHT ||
                    spread < AMDGPU_DM_MIN_SPREAD) {
                        DRM_DEBUG_KMS("DM: Invalid backlight caps: min=%d, max=%d\n",