--- hw/xfree86/drivers/modesetting/drmmode_display.c.orig	2016-08-29 15:12:50.802594679 +0800
+++ hw/xfree86/drivers/modesetting/drmmode_display.c	2016-08-29 16:11:40.984319198 +0800
@@ -983,7 +983,8 @@
     xf86MonPtr mon = output->MonInfo;
     DisplayModePtr i, m, preferred = NULL;
     int max_x = 0, max_y = 0;
-    float max_vrefresh = 0.0;
+    float max_vrefresh = 0.0, max_mon_vrefresh = 0.0;
+    XF86ConfMonitorPtr conf_monitor = output->conf_monitor;
 
     if (mon && GTF_SUPPORTED(mon->features.msc))
         return Modes;
@@ -999,8 +1000,16 @@
         max_vrefresh = max(max_vrefresh, xf86ModeVRefresh(m));
     }
 
-    max_vrefresh = max(max_vrefresh, 60.0);
-    max_vrefresh *= (1 + SYNC_TOLERANCE);
+    /* If we have monitor info, read its max vertical refesh 
+     * into max_mon_vrefresh from its reported modelines, 
+     * otherwise default to 60.0 Hz */
+    if (conf_monitor && conf_monitor->mon_n_vrefresh > 0) {
+        for (int index = 0; index < conf_monitor->mon_n_vrefresh; index++)
+            max_mon_vrefresh = max(max_mon_vrefresh, conf_monitor->mon_vrefresh[index].hi);
+    } else
+       max_mon_vrefresh = 60.0 * (1 + SYNC_TOLERANCE);
+
+    max_vrefresh = max(max_vrefresh, max_mon_vrefresh);
 
     m = xf86GetDefaultModes();
     xf86ValidateModesSize(output->scrn, m, max_x, max_y, 0);