[gdm] session: jump to VT up front for X sessions

[Ray Strode <halfline src gnome org>]

commit 5dcbc5ac1e8877787587d916a0bbcc6c4136a7c0
Author: Ray Strode <rstrode redhat com>
Date:   Fri Feb 27 07:49:17 2015 -0500

    session: jump to VT up front for X sessions
    
    It turns out that in order for X to work without being
    run as root, it needs to have its VT be active at start up.
    This is because it bails out of some of its logind codepaths
    if it gets given a "paused" device by logind, and then sometimes
    fails in its fallback code paths as it races to open
    /dev/dri/card0 while logind is still giving the user
    permissions to it.
    
    As a workaround, until X is fixed, this commit jumps to the VT up
    front before starting X. That adds flicker, which we'll address in
    a follow up commit.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=745031

 daemon/gdm-session.c |    7 ++++---
 1 files changed, 4 insertions(+), 3 deletions(-)
---
diff --git a/daemon/gdm-session.c b/daemon/gdm-session.c
index c66a6ff..27eb531 100644
--- a/daemon/gdm-session.c
+++ b/daemon/gdm-session.c
@@ -2945,10 +2945,11 @@ gdm_session_get_display_mode (GdmSession *self)
                 return GDM_SESSION_DISPLAY_MODE_LOGIND_MANAGED;
         }
 
-        /* user based X sessions start on a new VT now and are managed
-         * by logind
+        /* user based X sessions need us to allocate a VT for them
+         * and jump to it up front, because the X servers logind support
+         * currently relies on X running in the foreground VT.
          */
-        return GDM_SESSION_DISPLAY_MODE_LOGIND_MANAGED;
+        return GDM_SESSION_DISPLAY_MODE_NEW_VT;
 }
 
 void