From: jsg <jsg@openbsd.org>
Date: Thu, 14 Apr 2022 08:46:31 +0000 (+0000)
Subject: amd/display: set backlight only if required
X-Git-Url: http://artulab.com/gitweb/?a=commitdiff_plain;h=29f793d02200644cb5eeb2e226609eb72df6c1be;p=openbsd

amd/display: set backlight only if required

From Shirish S
a551e6629247dc84f8cea5d494542c532ea69161 in linux 5.15.y/5.15.34
4052287a75eb3fc0f487fcc5f768a38bede455c8 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 6620de38af5..6d365997afe 100644
--- a/sys/dev/pci/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/sys/dev/pci/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -3524,7 +3524,7 @@ static u32 convert_brightness_to_user(const struct amdgpu_dm_backlight_caps *cap
 				 max - min);
 }
 
-static int amdgpu_dm_backlight_set_level(struct amdgpu_display_manager *dm,
+static void amdgpu_dm_backlight_set_level(struct amdgpu_display_manager *dm,
 					 int bl_idx,
 					 u32 user_brightness)
 {
@@ -3552,7 +3552,8 @@ static int amdgpu_dm_backlight_set_level(struct amdgpu_display_manager *dm,
 			DRM_DEBUG("DM: Failed to update backlight on eDP[%d]\n", bl_idx);
 	}
 
-	return rc ? 0 : 1;
+	if (rc)
+		dm->actual_brightness[bl_idx] = user_brightness;
 }
 
 static int amdgpu_dm_backlight_update_status(struct backlight_device *bd)
@@ -9330,7 +9331,7 @@ static void amdgpu_dm_atomic_commit_tail(struct drm_atomic_state *state)
 	/* restore the backlight level */
 	for (i = 0; i < dm->num_of_edps; i++) {
 		if (dm->backlight_dev[i] &&
-		    (amdgpu_dm_backlight_get_level(dm, i) != dm->brightness[i]))
+		    (dm->actual_brightness[i] != dm->brightness[i]))
 			amdgpu_dm_backlight_set_level(dm, i, dm->brightness[i]);
 	}
 #endif
diff --git a/sys/dev/pci/drm/amd/display/amdgpu_dm/amdgpu_dm.h b/sys/dev/pci/drm/amd/display/amdgpu_dm/amdgpu_dm.h
index 1f304a7a028..391d1dc509b 100644
--- a/sys/dev/pci/drm/amd/display/amdgpu_dm/amdgpu_dm.h
+++ b/sys/dev/pci/drm/amd/display/amdgpu_dm/amdgpu_dm.h
@@ -446,6 +446,12 @@ struct amdgpu_display_manager {
 	 * cached backlight values.
 	 */
 	u32 brightness[AMDGPU_DM_MAX_NUM_EDP];
+	/**
+	 * @actual_brightness:
+	 *
+	 * last successfully applied backlight values.
+	 */
+	u32 actual_brightness[AMDGPU_DM_MAX_NUM_EDP];
 };
 
 enum dsc_clock_force_state {