[mutter/wip/display-no-wayland: 33/33] MonitorXrandr: follow the right order in applying the new configuration

[Giovanni Campagna <gcampagna src gnome org>]

commit 78b41e542ba484da0df5c886eddfc25d087034ae
Author: Giovanni Campagna <gcampagn redhat com>
Date:   Fri Aug 16 19:02:57 2013 +0200

    MonitorXrandr: follow the right order in applying the new configuration
    
    First disable CRTCs that should be off in the new configuration,
    then resize the framebuffer, then enable the new CRTCs.
    If we don't do that, and we're making the screen smaller, X complains
    with a BadMatch.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=705670

 src/core/monitor-xrandr.c |   90 +++++++++++++++++++++++++++------------------
 1 files changed, 54 insertions(+), 36 deletions(-)
---
diff --git a/src/core/monitor-xrandr.c b/src/core/monitor-xrandr.c
index 2a04993..af51e86 100644
--- a/src/core/monitor-xrandr.c
+++ b/src/core/monitor-xrandr.c
@@ -660,10 +660,13 @@ meta_monitor_manager_xrandr_apply_configuration (MetaMonitorManager *manager,
 
   meta_display_grab (meta_get_display ());
 
+  /* First compute the new size of the screen (framebuffer) */
   width = 0; height = 0;
   for (i = 0; i < n_crtcs; i++)
     {
       MetaCRTCInfo *crtc_info = crtcs[i];
+      MetaCRTC *crtc = crtc_info->crtc;
+      crtc->dirty = TRUE;
 
       if (crtc_info->mode == NULL)
         continue;
@@ -680,6 +683,54 @@ meta_monitor_manager_xrandr_apply_configuration (MetaMonitorManager *manager,
         }
     }
 
+  /* Second disable all newly disabled CRTCs, or CRTCs that in the previous
+     configuration would be outside the new framebuffer (otherwise X complains
+     loudly when resizing)
+     CRTC will be enabled again after resizing the FB
+  */
+  for (i = 0; i < n_crtcs; i++)
+    {
+      MetaCRTCInfo *crtc_info = crtcs[i];
+      MetaCRTC *crtc = crtc_info->crtc;
+
+      if (crtc_info->mode == NULL ||
+          crtc->rect.x + crtc->rect.width > width ||
+          crtc->rect.y + crtc->rect.height > height)
+        {
+          XRRSetCrtcConfig (manager_xrandr->xdisplay,
+                            manager_xrandr->resources,
+                            (XID)crtc->crtc_id,
+                            manager_xrandr->time,
+                            0, 0,
+                            None,
+                            RR_Rotate_0,
+                            NULL, 0);
+        }
+    }
+
+  /* Disable CRTCs not mentioned in the list */
+  for (i = 0; i < manager->n_crtcs; i++)
+    {
+      MetaCRTC *crtc = &manager->crtcs[i];
+
+      if (crtc->dirty)
+        {
+          crtc->dirty = FALSE;
+          continue;
+        }
+      if (crtc->current_mode == NULL)
+        continue;
+
+      XRRSetCrtcConfig (manager_xrandr->xdisplay,
+                        manager_xrandr->resources,
+                        (XID)crtc->crtc_id,
+                        manager_xrandr->time,
+                        0, 0,
+                        None,
+                        RR_Rotate_0,
+                        NULL, 0);
+    }
+
   g_assert (width > 0 && height > 0);
   /* The 'physical size' of an X screen is meaningless if that screen
    * can consist of many monitors. So just pick a size that make the
@@ -689,27 +740,17 @@ meta_monitor_manager_xrandr_apply_configuration (MetaMonitorManager *manager,
    */
   width_mm = (width / DPI_FALLBACK) * 25.4 + 0.5;
   height_mm = (height / DPI_FALLBACK) * 25.4 + 0.5;
+  meta_error_trap_push (meta_get_display ());
   XRRSetScreenSize (manager_xrandr->xdisplay, DefaultRootWindow (manager_xrandr->xdisplay),
                     width, height, width_mm, height_mm);
+  meta_error_trap_pop (meta_get_display ());
 
   for (i = 0; i < n_crtcs; i++)
     {
       MetaCRTCInfo *crtc_info = crtcs[i];
       MetaCRTC *crtc = crtc_info->crtc;
-      crtc->dirty = TRUE;
 
-      if (crtc_info->mode == NULL)
-        {
-          XRRSetCrtcConfig (manager_xrandr->xdisplay,
-                            manager_xrandr->resources,
-                            (XID)crtc->crtc_id,
-                            manager_xrandr->time,
-                            0, 0,
-                            None,
-                            RR_Rotate_0,
-                            NULL, 0);
-        }
-      else
+      if (crtc_info->mode != NULL)
         {
           MetaMonitorMode *mode;
           XID *outputs;
@@ -761,29 +802,6 @@ meta_monitor_manager_xrandr_apply_configuration (MetaMonitorManager *manager,
                                       output_info->is_presentation);
     }
 
-  /* Disable CRTCs not mentioned in the list */
-  for (i = 0; i < manager->n_crtcs; i++)
-    {
-      MetaCRTC *crtc = &manager->crtcs[i];
-
-      if (crtc->dirty)
-        {
-          crtc->dirty = FALSE;
-          continue;
-        }
-      if (crtc->current_mode == NULL)
-        continue;
-
-      XRRSetCrtcConfig (manager_xrandr->xdisplay,
-                        manager_xrandr->resources,
-                        (XID)crtc->crtc_id,
-                        manager_xrandr->time,
-                        0, 0,
-                        None,
-                        RR_Rotate_0,
-                        NULL, 0);
-    }
-
   meta_display_ungrab (meta_get_display ());
 }