drm/edid: Add 10 bpc quirk for LGD 764 panel in HP zBook 17 G2

The builtin eDP panel in the HP zBook 17 G2 supports 10 bpc,
as advertised by the Laptops product specs and verified via
injecting a fixed edid + photometer measurements, but edid
reports unknown depth, so drivers fall back to 6 bpc.

Add a quirk to get the full 10 bpc.

Cc: stable@vger.kernel.org
Signed-off-by: Mario Kleiner <mario.kleiner.de@gmail.com>
Acked-by: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1492787108-23959-1-git-send-email-mario.kleiner.de@gmail.com

Author: kleinerm

drivers/gpu/drm/drm_edid.c

@@ -80,6 +80,8 @@
 #define EDID_QUIRK_FORCE_12BPC			(1 << 9)
 /* Force 6bpc */
 #define EDID_QUIRK_FORCE_6BPC			(1 << 10)
+/* Force 10bpc */
+#define EDID_QUIRK_FORCE_10BPC			(1 << 11)
 
 struct detailed_mode_closure {
 	struct drm_connector *connector;
@@ -122,6 +124,9 @@ static const struct edid_quirk {
 	{ "FCM", 13600, EDID_QUIRK_PREFER_LARGE_75 |
 	  EDID_QUIRK_DETAILED_IN_CM },
 
+	/* LGD panel of HP zBook 17 G2, eDP 10 bpc, but reports unknown bpc */
+	{ "LGD", 764, EDID_QUIRK_FORCE_10BPC },
+
 	/* LG Philips LCD LP154W01-A5 */
 	{ "LPL", 0, EDID_QUIRK_DETAILED_USE_MAXIMUM_SIZE },
 	{ "LPL", 0x2a00, EDID_QUIRK_DETAILED_USE_MAXIMUM_SIZE },
@@ -4244,6 +4249,9 @@ int drm_add_edid_modes(struct drm_connector *connector, struct edid *edid)
 	if (quirks & EDID_QUIRK_FORCE_8BPC)
 		connector->display_info.bpc = 8;
 
+	if (quirks & EDID_QUIRK_FORCE_10BPC)
+		connector->display_info.bpc = 10;
+
 	if (quirks & EDID_QUIRK_FORCE_12BPC)
 		connector->display_info.bpc = 12;