Merge tag 'v5.9-rc4' into drm-next

Backmerge 5.9-rc4 as there is a nasty qxl conflict
that needs to be resolved.

Signed-off-by: Dave Airlie <airlied@redhat.com>

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c

@@ -2871,12 +2871,18 @@ static int amdgpu_dm_mode_config_init(struct amdgpu_device *adev)
 				    &dm_atomic_state_funcs);
 
 	r = amdgpu_display_modeset_create_props(adev);
-	if (r)
+	if (r) {
+		dc_release_state(state->context);
+		kfree(state);
 		return r;
+	}
 
 	r = amdgpu_dm_audio_init(adev);
-	if (r)
+	if (r) {
+		dc_release_state(state->context);
+		kfree(state);
 		return r;
+	}
 
 	return 0;
 }
@@ -2893,6 +2899,8 @@ static void amdgpu_dm_update_backlight_caps(struct amdgpu_display_manager *dm)
 #if defined(CONFIG_ACPI)
 	struct amdgpu_dm_backlight_caps caps;
 
+	memset(&caps, 0, sizeof(caps));
+
 	if (dm->backlight_caps.caps_valid)
 		return;
 
@@ -2931,51 +2939,50 @@ static int set_backlight_via_aux(struct dc_link *link, uint32_t brightness)
 	return rc ? 0 : 1;
 }
 
-static u32 convert_brightness(const struct amdgpu_dm_backlight_caps *caps,
-			      const uint32_t user_brightness)
+static int get_brightness_range(const struct amdgpu_dm_backlight_caps *caps,
+				unsigned *min, unsigned *max)
 {
-	u32 min, max, conversion_pace;
-	u32 brightness = user_brightness;
-
 	if (!caps)
-		goto out;
+		return 0;
 
-	if (!caps->aux_support) {
-		max = caps->max_input_signal;
-		min = caps->min_input_signal;
-		/*
-		 * The brightness input is in the range 0-255
-		 * It needs to be rescaled to be between the
-		 * requested min and max input signal
-		 * It also needs to be scaled up by 0x101 to
-		 * match the DC interface which has a range of
-		 * 0 to 0xffff
-		 */
-		conversion_pace = 0x101;
-		brightness =
-			user_brightness
-			* conversion_pace
-			* (max - min)
-			/ AMDGPU_MAX_BL_LEVEL
-			+ min * conversion_pace;
+	if (caps->aux_support) {
+		// Firmware limits are in nits, DC API wants millinits.
+		*max = 1000 * caps->aux_max_input_signal;
+		*min = 1000 * caps->aux_min_input_signal;
 	} else {
-		/* TODO
-		 * We are doing a linear interpolation here, which is OK but
-		 * does not provide the optimal result. We probably want
-		 * something close to the Perceptual Quantizer (PQ) curve.
-		 */
-		max = caps->aux_max_input_signal;
-		min = caps->aux_min_input_signal;
-
-		brightness = (AMDGPU_MAX_BL_LEVEL - user_brightness) * min
-			       + user_brightness * max;
-		// Multiple the value by 1000 since we use millinits
-		brightness *= 1000;
-		brightness = DIV_ROUND_CLOSEST(brightness, AMDGPU_MAX_BL_LEVEL);
+		// Firmware limits are 8-bit, PWM control is 16-bit.
+		*max = 0x101 * caps->max_input_signal;
+		*min = 0x101 * caps->min_input_signal;
 	}
+	return 1;
+}
 
-out:
-	return brightness;
+static u32 convert_brightness_from_user(const struct amdgpu_dm_backlight_caps *caps,
+					uint32_t brightness)
+{
+	unsigned min, max;
+
+	if (!get_brightness_range(caps, &min, &max))
+		return brightness;
+
+	// Rescale 0..255 to min..max
+	return min + DIV_ROUND_CLOSEST((max - min) * brightness,
+				       AMDGPU_MAX_BL_LEVEL);
+}
+
+static u32 convert_brightness_to_user(const struct amdgpu_dm_backlight_caps *caps,
+				      uint32_t brightness)
+{
+	unsigned min, max;
+
+	if (!get_brightness_range(caps, &min, &max))
+		return brightness;
+
+	if (brightness < min)
+		return 0;
+	// Rescale min..max to 0..255
+	return DIV_ROUND_CLOSEST(AMDGPU_MAX_BL_LEVEL * (brightness - min),
+				 max - min);
 }
 
 static int amdgpu_dm_backlight_update_status(struct backlight_device *bd)
@@ -2991,7 +2998,7 @@ static int amdgpu_dm_backlight_update_status(struct backlight_device *bd)
 
 	link = (struct dc_link *)dm->backlight_link;
 
-	brightness = convert_brightness(&caps, bd->props.brightness);
+	brightness = convert_brightness_from_user(&caps, bd->props.brightness);
 	// Change brightness based on AUX property
 	if (caps.aux_support)
 		return set_backlight_via_aux(link, brightness);
@@ -3008,7 +3015,7 @@ static int amdgpu_dm_backlight_get_brightness(struct backlight_device *bd)
 
 	if (ret == DC_ERROR_UNEXPECTED)
 		return bd->props.brightness;
-	return ret;
+	return convert_brightness_to_user(&dm->backlight_caps, ret);
 }
 
 static const struct backlight_ops amdgpu_dm_backlight_ops = {