Extend the DBus XRandR protocol to expose cloning restriction

Turns out that even if two outputs say that they can be controlled
by a given CRTC, you can't configure them in the same CRTC unless
they are marked as "possible clones" one of the other.
This can further restrict the configuration options, so we need
to expose this limitation in the DBus API.

https://bugzilla.gnome.org/show_bug.cgi?id=705670

src/core/monitor-private.h

@@ -70,6 +70,9 @@ struct _MetaOutput
   MetaCRTC **possible_crtcs;
   unsigned int n_possible_crtcs;
 
+  MetaOutput **possible_clones;
+  unsigned int n_possible_clones;
+
   /* The low-level bits used to build the high-level info
      in MetaMonitorInfo
 

src/core/monitor.c

@@ -144,6 +144,8 @@ make_dummy_monitor_config (MetaMonitorManager *manager)
   manager->outputs[0].n_possible_crtcs = 1;
   manager->outputs[0].possible_crtcs = g_new0 (MetaCRTC *, 1);
   manager->outputs[0].possible_crtcs[0] = &manager->crtcs[0];
+  manager->outputs[0].n_possible_clones = 0;
+  manager->outputs[0].possible_clones = g_new0 (MetaOutput *, 0);
 }
 
 #ifdef HAVE_RANDR
@@ -273,6 +275,17 @@ read_monitor_infos_from_xrandr (MetaMonitorManager *manager)
                   }
               }
 
+            meta_output->n_possible_clones = output->nclone;
+            meta_output->possible_clones = g_new0 (MetaOutput *, meta_output->n_possible_clones);
+            /* We can build the list of clones now, because we don't have the list of outputs
+               yet, so temporarily set the pointers to the bare XIDs, and then we'll fix them
+               in a second pass
+            */
+            for (j = 0; j < (unsigned)output->nclone; j++)
+              {
+                meta_output->possible_clones = GINT_TO_POINTER (output->clones[j]);
+              }
+
             meta_output->is_primary = ((XID)meta_output->output_id == primary_output);
             meta_output->is_presentation = FALSE;
 
@@ -284,6 +297,28 @@ read_monitor_infos_from_xrandr (MetaMonitorManager *manager)
 
     manager->n_outputs = n_actual_outputs;
 
+    /* Now fix the clones */
+    for (i = 0; i < manager->n_outputs; i++)
+      {
+        MetaOutput *meta_output;
+
+        meta_output = &manager->outputs[i];
+
+        for (j = 0; j < meta_output->n_possible_clones; j++)
+          {
+            RROutput clone = GPOINTER_TO_INT (meta_output->possible_clones[j]);
+
+            for (k = 0; k < manager->n_outputs; k++)
+              {
+                if (clone == (XID)manager->outputs[k].output_id)
+                  {
+                    meta_output->possible_clones[j] = &manager->outputs[k];
+                    break;
+                  }
+              }
+          }
+      }
+
     XRRFreeScreenResources (resources);
 }
 
@@ -463,6 +498,7 @@ free_output_array (MetaOutput *old_outputs,
       g_free (old_outputs[i].serial);
       g_free (old_outputs[i].modes);
       g_free (old_outputs[i].possible_crtcs);
+      g_free (old_outputs[i].possible_clones);
     }
 
   g_free (old_outputs);
@@ -567,7 +603,7 @@ handle_get_resources (MetaDBusDisplayConfig *skeleton,
   unsigned int i, j;
 
   g_variant_builder_init (&crtc_builder, G_VARIANT_TYPE ("a(uxiiiiiuaua{sv})"));
-  g_variant_builder_init (&output_builder, G_VARIANT_TYPE ("a(uxiausaua{sv})"));
+  g_variant_builder_init (&output_builder, G_VARIANT_TYPE ("a(uxiausauaua{sv})"));
   g_variant_builder_init (&mode_builder, G_VARIANT_TYPE ("a(uxuud)"));
 
   for (i = 0; i < manager->n_crtcs; i++)
@@ -594,7 +630,7 @@ handle_get_resources (MetaDBusDisplayConfig *skeleton,
   for (i = 0; i < manager->n_outputs; i++)
     {
       MetaOutput *output = &manager->outputs[i];
-      GVariantBuilder crtcs, modes, properties;
+      GVariantBuilder crtcs, modes, clones, properties;
 
       g_variant_builder_init (&crtcs, G_VARIANT_TYPE ("au"));
       for (j = 0; j < output->n_possible_crtcs; j++)
@@ -606,6 +642,11 @@ handle_get_resources (MetaDBusDisplayConfig *skeleton,
         g_variant_builder_add (&modes, "u",
                                (unsigned)(output->modes[j] - manager->modes));
 
+      g_variant_builder_init (&clones, G_VARIANT_TYPE ("au"));
+      for (j = 0; j < output->n_possible_clones; j++)
+        g_variant_builder_add (&clones, "u",
+                               (unsigned)(output->possible_clones[j] - manager->outputs));
+
       g_variant_builder_init (&properties, G_VARIANT_TYPE ("a{sv}"));
       g_variant_builder_add (&properties, "{sv}", "vendor",
                              g_variant_new_string (output->vendor));
@@ -620,13 +661,14 @@ handle_get_resources (MetaDBusDisplayConfig *skeleton,
       g_variant_builder_add (&properties, "{sv}", "presentation",
                              g_variant_new_boolean (output->is_presentation));
 
-      g_variant_builder_add (&output_builder, "(uxiausaua{sv})",
+      g_variant_builder_add (&output_builder, "(uxiausauaua{sv})",
                              i, /* ID */
                              output->output_id,
                              (int)(output->crtc ? output->crtc - manager->crtcs : -1),
                              &crtcs,
                              output->name,
                              &modes,
+                             &clones,
                              &properties);
     }
 

src/xrandr.xml

@@ -76,6 +76,11 @@
 	* s name: the name of the connector to which the output is attached
 	          (like VGA1 or HDMI)
 	* au modes: valid modes for this output
+	* au clones: valid clones for this output, ie other outputs that
+	             can be assigned the same CRTC as this one; if you
+	             want to mirror two outputs that don't have each other
+	             in the clone list, you must configure two different
+	             CRTCs for the same geometry
 	* a{sv} properties: other high-level properties that affect this
 	                    output; they are not necessarily reflected in
 			    the hardware.
@@ -123,7 +128,7 @@
     <method name="GetResources">
       <arg name="serial" direction="out" type="u" />
       <arg name="crtcs" direction="out" type="a(uxiiiiiuaua{sv})" />
-      <arg name="outputs" direction="out" type="a(uxiausaua{sv})" />
+      <arg name="outputs" direction="out" type="a(uxiausauaua{sv})" />
       <arg name="modes" direction="out" type="a(uxuud)" />
     </method>