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

BugLink: http://bugs.launchpad.net/bugs/1694621

commit e345da82 upstream.

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.
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.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>

drivers/gpu/drm/drm_edid.c

@@ -75,6 +75,8 @@
 #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;
@@ -117,6 +119,9 @@ static 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 },
@@ -3834,6 +3839,9 @@ 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;