From 0ad3e64eb46d8c47de3af552e282894e3893e973 Mon Sep 17 00:00:00 2001
From: Alex Deucher <alexander.deucher@amd.com>
Date: Thu, 10 Dec 2020 01:45:12 -0500
Subject: [PATCH 3/4] drm/amdgpu/display: handle aux backlight in backlight_get_brightness
Git-commit: 0ad3e64eb46d8c47de3af552e282894e3893e973
Patch-mainline: v5.12-rc3
References: bsc#1180749

Need to fetch it via aux.

Reviewed-by: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 .../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 24 +++++++++++++++----
 1 file changed, 20 insertions(+), 4 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 78720a25c13f..0bc9a06b3f15 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -3258,11 +3258,27 @@ static int amdgpu_dm_backlight_update_status(struct backlight_device *bd)
 static int amdgpu_dm_backlight_get_brightness(struct backlight_device *bd)
 {
 	struct amdgpu_display_manager *dm = bl_get_data(bd);
-	int ret = dc_link_get_backlight_level(dm->backlight_link);
+	struct amdgpu_dm_backlight_caps caps;
+
+	amdgpu_dm_update_backlight_caps(dm);
+	caps = dm->backlight_caps;
 
-	if (ret == DC_ERROR_UNEXPECTED)
-		return bd->props.brightness;
-	return convert_brightness_to_user(&dm->backlight_caps, ret);
+	if (caps.aux_support) {
+		struct dc_link *link = (struct dc_link *)dm->backlight_link;
+		u32 avg, peak;
+		bool rc;
+
+		rc = dc_link_get_backlight_level_nits(link, &avg, &peak);
+		if (!rc)
+			return bd->props.brightness;
+		return convert_brightness_to_user(&caps, avg);
+	} else {
+		int ret = dc_link_get_backlight_level(dm->backlight_link);
+
+		if (ret == DC_ERROR_UNEXPECTED)
+			return bd->props.brightness;
+		return convert_brightness_to_user(&caps, ret);
+	}
 }
 
 static const struct backlight_ops amdgpu_dm_backlight_ops = {
-- 
2.26.2