drm/edid: Fix preferred mode parse for EDID 1.4

In 1.4, the first detailed mode is always the preferred mode.  The bit
that used to mean that, now means "this mode is the physical size in
pixels".

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

drivers/gpu/drm/drm_edid.c

@@ -1295,7 +1295,10 @@ static int add_detailed_info(struct drm_connector *connector,
 
 	for (i = 0; i < EDID_DETAILED_TIMINGS; i++) {
 		struct detailed_timing *timing = &edid->detailed_timings[i];
-		int preferred = (i == 0) && (edid->features & DRM_EDID_FEATURE_PREFERRED_TIMING);
+		int preferred = (i == 0);
+
+		if (preferred && edid->version == 1 && edid->revision < 4)
+			preferred = (edid->features & DRM_EDID_FEATURE_PREFERRED_TIMING);
 
 		/* In 1.0, only timings are allowed */
 		if (!timing->pixel_clock && edid->version == 1 &&