Created attachment 157989 [details] [review]
[GdkScreenX11] Add heuristic for pre XRandR 1.3 drivers

Currently gdk_screen_get_primary_monitor just returns the first monitor,
in this case but both the panel and now gnome-shell use an additional
heuristic to prefer LVDS as primary if present.

Move this heuristic to gdk_screen_get_primary_monitor to avoid duplicating
it all over the place.

Created attachment 158008 [details] [review]
Add heuristic for pre XRandR 1.3 drivers

Currently gdk_screen_get_primary_monitor just returns the first monitor,
in this case but both the panel and now gnome-shell use an additional
heuristic to prefer LVDS as primary if present.

Move this heuristic to gdk_screen_get_primary_monitor to avoid duplicating
it all over the place.

The fallback heuristic is also used when no primary output is set.

Review of attachment 158008 [details] [review]:

Looks good to me, modulo the one minor comment. Please commit. I'll cherry-pick it to the stable 2.20 branch, once I create it.

::: gdk/x11/gdkscreen-x11.c
@@ +772,3 @@
 	XRRGetOutputInfo (dpy, resources, resources->outputs[i]);
 
+      if (primary_output != None && resources->outputs[i] == primary_output)

I think the != None check is redundant here, None will never be returned in the outputs array.

Pushed without the redundant None check.