[gnome-flashback] display-config: skip outputs with no crtcs

[Alberts Muktupāvels <muktupavels src gnome org>]

commit b72e79dbb642f892bc436cf8a28093d7a7967ed2
Author: Rui Matos <tiagomatos gmail com>
Date:   Tue Oct 27 15:43:58 2015 +0100

    display-config: skip outputs with no crtcs
    
    Outputs with no crtcs shouldn't happen, but if it does we should
    ignore them, instead of possibly crashing later.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=756796

 .../libdisplay-config/flashback-monitor-manager.c  |   66 ++++++++++++--------
 1 files changed, 39 insertions(+), 27 deletions(-)
---
diff --git a/gnome-flashback/libdisplay-config/flashback-monitor-manager.c 
b/gnome-flashback/libdisplay-config/flashback-monitor-manager.c
index b2e12b6..8812dbd 100644
--- a/gnome-flashback/libdisplay-config/flashback-monitor-manager.c
+++ b/gnome-flashback/libdisplay-config/flashback-monitor-manager.c
@@ -813,6 +813,43 @@ output_get_modes (FlashbackMonitorManager *manager,
     meta_output->preferred_mode = meta_output->modes[0];
 }
 
+static void
+output_get_crtcs (FlashbackMonitorManager *manager,
+                  MetaOutput              *meta_output,
+                  XRROutputInfo           *output)
+{
+  guint j, k;
+  guint n_actual_crtcs;
+
+  meta_output->possible_crtcs = g_new0 (MetaCRTC *, output->ncrtc);
+
+  n_actual_crtcs = 0;
+  for (j = 0; j < (unsigned)output->ncrtc; j++)
+    {
+      for (k = 0; k < manager->n_crtcs; k++)
+        {
+          if ((XID)manager->crtcs[k].crtc_id == output->crtcs[j])
+            {
+              meta_output->possible_crtcs[n_actual_crtcs] = &manager->crtcs[k];
+              n_actual_crtcs += 1;
+              break;
+            }
+        }
+    }
+
+  meta_output->n_possible_crtcs = n_actual_crtcs;
+
+  meta_output->crtc = NULL;
+  for (j = 0; j < manager->n_crtcs; j++)
+    {
+      if ((XID)manager->crtcs[j].crtc_id == output->crtc)
+        {
+          meta_output->crtc = &manager->crtcs[j];
+          break;
+        }
+    }
+}
+
 static char *
 get_xmode_name (XRRModeInfo *xmode)
 {
@@ -1338,32 +1375,7 @@ read_current_config (FlashbackMonitorManager *manager)
 
           output_get_tile_info (priv, meta_output);
           output_get_modes (manager, meta_output, output);
-
-          meta_output->n_possible_crtcs = output->ncrtc;
-          meta_output->possible_crtcs = g_new0 (MetaCRTC *, meta_output->n_possible_crtcs);
-
-          for (j = 0; j < (unsigned)output->ncrtc; j++)
-            {
-              for (k = 0; k < manager->n_crtcs; k++)
-                {
-                  if ((XID)manager->crtcs[k].crtc_id == output->crtcs[j])
-                    {
-                      meta_output->possible_crtcs[j] = &manager->crtcs[k];
-                      break;
-                    }
-                }
-            }
-
-          meta_output->crtc = NULL;
-
-          for (j = 0; j < manager->n_crtcs; j++)
-            {
-              if ((XID)manager->crtcs[j].crtc_id == output->crtc)
-                {
-                  meta_output->crtc = &manager->crtcs[j];
-                  break;
-                }
-            }
+          output_get_crtcs (manager, meta_output, output);
 
           meta_output->n_possible_clones = output->nclone;
           meta_output->possible_clones = g_new0 (MetaOutput *, meta_output->n_possible_clones);
@@ -1387,7 +1399,7 @@ read_current_config (FlashbackMonitorManager *manager)
         else
           meta_output->backlight = -1;
 
-        if (meta_output->n_modes == 0)
+        if (meta_output->n_modes == 0 || meta_output->n_possible_crtcs == 0)
           clear_output (meta_output);
         else
           n_actual_outputs++;