diff --git a/hw/xfree86/common/xf86platformBus.c b/hw/xfree86/common/xf86platformBus.c
index 39b32484e..fc17d1504 100644
--- a/hw/xfree86/common/xf86platformBus.c
+++ b/hw/xfree86/common/xf86platformBus.c
@@ -286,6 +286,7 @@ xf86platformProbe(void)
 {
     int i;
     Bool pci = TRUE;
+    XF86ConfOutputClassPtr cl;
 
     config_odev_probe(xf86PlatformDeviceProbe);
 
@@ -301,6 +302,24 @@ xf86platformProbe(void)
         }
     }
 
+    /* First see if there is an OutputClass match marking a device as primary */
+    for (i = 0; i < xf86_num_platform_devices; i++) {
+        struct xf86_platform_device *dev = &xf86_platform_devices[i];
+        for (cl = xf86configptr->conf_outputclass_lst; cl; cl = cl->list.next) {
+            if (!OutputClassMatches(cl, dev))
+                continue;
+
+            if (xf86CheckBoolOption(cl->option_lst, "PrimaryGPU", FALSE)) {
+                xf86Msg(X_CONFIG, "OutputClass \"%s\" setting %s as PrimaryGPU\n",
+                        cl->identifier, dev->attribs->path);
+                primaryBus.type = BUS_PLATFORM;
+                primaryBus.id.plat = dev;
+                return 0;
+            }
+        }
+    }
+
+    /* Then check for pci_device_is_boot_vga() */
     for (i = 0; i < xf86_num_platform_devices; i++) {
         struct xf86_platform_device *dev = &xf86_platform_devices[i];
 
diff --git a/hw/xfree86/man/xorg.conf.man b/hw/xfree86/man/xorg.conf.man
index 8928a53b9..79b71a84b 100644
--- a/hw/xfree86/man/xorg.conf.man
+++ b/hw/xfree86/man/xorg.conf.man
@@ -1285,11 +1285,21 @@ When an output device has been matched to the
 .B OutputClass
 section, any
 .B Option
-entries are applied to the device. See the
+entries are applied to the device. One
+.B OutputClass
+specific
+.B Option
+is recognized. See the
 .B Device
 section below for a description of the remaining
 .B Option
 entries.
+.TP 7
+.BI "Option \*qPrimaryGPU\*q \*q" boolean \*q
+This option specifies that the matched device should be treated as the
+primary GPU, replacing the selection of the GPU used as output by the
+firmware. If multiple output devices match an OutputClass section with
+the PrimaryGPU option set, the first one enumerated becomes the primary GPU.
 .SH "DEVICE SECTION"
 The config file may have multiple
 .B Device