From: jsg <jsg@openbsd.org>
Date: Mon, 9 May 2022 09:00:01 +0000 (+0000)
Subject: drm/i915: Check EDID for HDR static metadata when choosing blc
X-Git-Url: http://artulab.com/gitweb/?a=commitdiff_plain;h=8264a98c61343583b89078a0adb1da60876cf6cc;p=openbsd

drm/i915: Check EDID for HDR static metadata when choosing blc

From Jouni Hogander
67434e132b8c9d3fb59f0bc27da6d0a0488cf92b in linux 5.15.y/5.15.38
c05d8332f5d23fa3b521911cbe55a2b67fb21248 in mainline linux
---

diff --git a/sys/dev/pci/drm/i915/display/intel_dp_aux_backlight.c b/sys/dev/pci/drm/i915/display/intel_dp_aux_backlight.c
index c82f8febe73..e7b90863aa4 100644
--- a/sys/dev/pci/drm/i915/display/intel_dp_aux_backlight.c
+++ b/sys/dev/pci/drm/i915/display/intel_dp_aux_backlight.c
@@ -96,6 +96,14 @@
 
 #define INTEL_EDP_BRIGHTNESS_OPTIMIZATION_1                            0x359
 
+enum intel_dp_aux_backlight_modparam {
+	INTEL_DP_AUX_BACKLIGHT_AUTO = -1,
+	INTEL_DP_AUX_BACKLIGHT_OFF = 0,
+	INTEL_DP_AUX_BACKLIGHT_ON = 1,
+	INTEL_DP_AUX_BACKLIGHT_FORCE_VESA = 2,
+	INTEL_DP_AUX_BACKLIGHT_FORCE_INTEL = 3,
+};
+
 /* Intel EDP backlight callbacks */
 static bool
 intel_dp_aux_supports_hdr_backlight(struct intel_connector *connector)
@@ -125,6 +133,24 @@ intel_dp_aux_supports_hdr_backlight(struct intel_connector *connector)
 		return false;
 	}
 
+	/*
+	 * If we don't have HDR static metadata there is no way to
+	 * runtime detect used range for nits based control. For now
+	 * do not use Intel proprietary eDP backlight control if we
+	 * don't have this data in panel EDID. In case we find panel
+	 * which supports only nits based control, but doesn't provide
+	 * HDR static metadata we need to start maintaining table of
+	 * ranges for such panels.
+	 */
+	if (i915->params.enable_dpcd_backlight != INTEL_DP_AUX_BACKLIGHT_FORCE_INTEL &&
+	    !(connector->base.hdr_sink_metadata.hdmi_type1.metadata_type &
+	      BIT(HDMI_STATIC_METADATA_TYPE1))) {
+		drm_info(&i915->drm,
+			 "Panel is missing HDR static metadata. Possible support for Intel HDR backlight interface is not used. If your backlight controls don't work try booting with i915.enable_dpcd_backlight=%d. needs this, please file a _new_ bug report on drm/i915, see " FDO_BUG_URL " for details.\n",
+			 INTEL_DP_AUX_BACKLIGHT_FORCE_INTEL);
+		return false;
+	}
+
 	panel->backlight.edp.intel.sdr_uses_aux =
 		tcon_cap[2] & INTEL_EDP_SDR_TCON_BRIGHTNESS_AUX_CAP;
 
@@ -373,14 +399,6 @@ static const struct intel_panel_bl_funcs intel_dp_vesa_bl_funcs = {
 	.get = intel_dp_aux_vesa_get_backlight,
 };
 
-enum intel_dp_aux_backlight_modparam {
-	INTEL_DP_AUX_BACKLIGHT_AUTO = -1,
-	INTEL_DP_AUX_BACKLIGHT_OFF = 0,
-	INTEL_DP_AUX_BACKLIGHT_ON = 1,
-	INTEL_DP_AUX_BACKLIGHT_FORCE_VESA = 2,
-	INTEL_DP_AUX_BACKLIGHT_FORCE_INTEL = 3,
-};
-
 int intel_dp_aux_init_backlight_funcs(struct intel_connector *connector)
 {
 	struct drm_device *dev = connector->base.dev;