From db7e9f8306716c4338b7de01cb1026d8e1dd8afa Mon Sep 17 00:00:00 2001

From: Ray Strode <rstrode@redhat.com>

Date: Tue, 7 Aug 2018 14:04:44 -0400

Subject: [PATCH 17/48] session-worker: don't switch VTs if we're already on

 the right VT

commit 5b5dccbd shows that switching VTs to the same VT isn't

exactly a no-op. In order to prevent unnecessary wakeups, avoid

switching VTs if the worker is already on the correct VT.

---

 daemon/gdm-session-worker.c | 22 ++++++++++++++++------

 1 file changed, 16 insertions(+), 6 deletions(-)

diff --git a/daemon/gdm-session-worker.c b/daemon/gdm-session-worker.c

index 0322037e0..fd6470bab 100644

--- a/daemon/gdm-session-worker.c

+++ b/daemon/gdm-session-worker.c

@@ -936,91 +936,101 @@ fix_terminal_vt_mode (GdmSessionWorker  *worker,

         if (ioctl (tty_fd, KDGETMODE, &kernel_display_mode) < 0) {

                 g_debug ("GdmSessionWorker: couldn't query kernel display mode: %m");

                 succeeded = FALSE;

         }

         if (kernel_display_mode == KD_TEXT) {

                 goto out;

         }

         /* VT is in the anti-social state of VT_AUTO + KD_GRAPHICS,

          * fix it.

          */

         succeeded = handle_terminal_vt_switches (worker, tty_fd);

         mode_fixed = TRUE;

 out:

         if (!succeeded) {

                 g_error ("GdmSessionWorker: couldn't set up terminal, aborting...");

                 return;

         }

         g_debug ("GdmSessionWorker: VT mode did %sneed to be fixed",

                  mode_fixed? "" : "not ");

 }

 static void

 jump_to_vt (GdmSessionWorker  *worker,

             int                vt_number)

 {

         int fd;

         int active_vt_tty_fd;

+        int active_vt = -1;

+        struct vt_stat vt_state = { 0 };

         g_debug ("GdmSessionWorker: jumping to VT %d", vt_number);

         active_vt_tty_fd = open ("/dev/tty0", O_RDWR | O_NOCTTY);

         if (worker->priv->session_tty_fd != -1) {

                 fd = worker->priv->session_tty_fd;

                 g_debug ("GdmSessionWorker: first setting graphics mode to prevent flicker");

                 if (ioctl (fd, KDSETMODE, KD_GRAPHICS) < 0) {

                         g_debug ("GdmSessionWorker: couldn't set graphics mode: %m");

                 }

                 /* It's possible that the current VT was left in a broken

                  * combination of states (KD_GRAPHICS with VT_AUTO), that

                  * can't be switched away from.  This call makes sure things

                  * are set in a way that VT_ACTIVATE should work and

                  * VT_WAITACTIVE shouldn't hang.

                  */

                 fix_terminal_vt_mode (worker, active_vt_tty_fd);

         } else {

                 fd = active_vt_tty_fd;

         }

         handle_terminal_vt_switches (worker, fd);

-        if (ioctl (fd, VT_ACTIVATE, vt_number) < 0) {

-                g_debug ("GdmSessionWorker: couldn't initiate jump to VT %d: %m",

-                         vt_number);

-        } else if (ioctl (fd, VT_WAITACTIVE, vt_number) < 0) {

-                g_debug ("GdmSessionWorker: couldn't finalize jump to VT %d: %m",

-                         vt_number);

+        if (ioctl (fd, VT_GETSTATE, &vt_state) <= 0) {

+                g_debug ("GdmSessionWorker: couldn't get current VT: %m");

+        } else {

+                active_vt = vt_state.v_active;

+        }

+

+        if (active_vt != vt_number) {

+                if (ioctl (fd, VT_ACTIVATE, vt_number) < 0) {

+                        g_debug ("GdmSessionWorker: couldn't initiate jump to VT %d: %m",

+                                 vt_number);

+                } else if (ioctl (fd, VT_WAITACTIVE, vt_number) < 0) {

+                        g_debug ("GdmSessionWorker: couldn't finalize jump to VT %d: %m",

+                                 vt_number);

+                }

         }

         close (active_vt_tty_fd);

 }

 static void

 gdm_session_worker_set_state (GdmSessionWorker      *worker,

                               GdmSessionWorkerState  state)

 {

         if (worker->priv->state == state)

                 return;

         worker->priv->state = state;

         g_object_notify (G_OBJECT (worker), "state");

 }

 static void

 gdm_session_worker_uninitialize_pam (GdmSessionWorker *worker,

                                      int               status)

 {

         g_debug ("GdmSessionWorker: uninitializing PAM");

         if (worker->priv->pam_handle == NULL)

                 return;

         gdm_session_worker_get_username (worker, NULL);

         if (worker->priv->state >= GDM_SESSION_WORKER_STATE_SESSION_OPENED) {

                 pam_close_session (worker->priv->pam_handle, 0);

                 gdm_session_auditor_report_logout (worker->priv->auditor);

-- 

2.26.0