backend: Move GPU ownership from the monitor manager to the backend

Lets work towards making MetaMonitorManager about managing monitors, and
not about managing GPUs. This changes other units to keep a pointer to
the backend instead of a monitor manager, in case their ownership
changed, or their main usage of the monitor manager was to look up GPUs.

https://gitlab.gnome.org/GNOME/mutter/issues/548
https://gitlab.gnome.org/GNOME/mutter/merge_requests/525

src/backends/x11/cm/meta-backend-x11-cm.c

@@ -28,6 +28,7 @@
 
 #include "backends/meta-backend-private.h"
 #include "backends/x11/meta-cursor-renderer-x11.h"
+#include "backends/x11/meta-gpu-xrandr.h"
 #include "backends/x11/meta-input-settings-x11.h"
 #include "backends/x11/meta-monitor-manager-xrandr.h"
 #include "backends/x11/cm/meta-renderer-x11-cm.h"
@@ -389,6 +390,16 @@ meta_backend_x11_cm_translate_crossing_event (MetaBackendX11 *x11,
 static void
 meta_backend_x11_cm_init (MetaBackendX11Cm *backend_x11_cm)
 {
+  MetaGpuXrandr *gpu_xrandr;
+
+  /*
+   * The X server deals with multiple GPUs for us, so we just see what the X
+   * server gives us as one single GPU, even though it may actually be backed
+   * by multiple.
+   */
+  gpu_xrandr = meta_gpu_xrandr_new (META_BACKEND_X11 (backend_x11_cm));
+  meta_backend_add_gpu (META_BACKEND (backend_x11_cm),
+                        META_GPU (gpu_xrandr));
 }
 
 static void

src/backends/x11/meta-crtc-xrandr.c

@@ -39,6 +39,7 @@
 #include <stdlib.h>
 #include <xcb/randr.h>
 
+#include "backends/meta-backend-private.h"
 #include "backends/meta-crtc.h"
 #include "backends/x11/meta-crtc-xrandr.h"
 #include "backends/x11/meta-gpu-xrandr.h"
@@ -60,7 +61,9 @@ meta_crtc_xrandr_set_config (MetaCrtc            *crtc,
 {
   MetaGpu *gpu = meta_crtc_get_gpu (crtc);
   MetaGpuXrandr *gpu_xrandr = META_GPU_XRANDR (gpu);
-  MetaMonitorManager *monitor_manager = meta_gpu_get_monitor_manager (gpu);
+  MetaBackend *backend = meta_gpu_get_backend (gpu);
+  MetaMonitorManager *monitor_manager =
+    meta_backend_get_monitor_manager (backend);
   MetaMonitorManagerXrandr *monitor_manager_xrandr =
     META_MONITOR_MANAGER_XRANDR (monitor_manager);
   Display *xdisplay;

src/backends/x11/meta-gpu-xrandr.c

@@ -31,7 +31,9 @@
 #include <X11/extensions/dpms.h>
 #include <X11/Xlibint.h>
 
+#include "backends/meta-backend-private.h"
 #include "backends/meta-output.h"
+#include "backends/x11/meta-backend-x11.h"
 #include "backends/x11/meta-crtc-xrandr.h"
 #include "backends/x11/meta-monitor-manager-xrandr.h"
 #include "backends/x11/meta-output-xrandr.h"
@@ -86,7 +88,9 @@ meta_gpu_xrandr_read_current (MetaGpu  *gpu,
                               GError  **error)
 {
   MetaGpuXrandr *gpu_xrandr = META_GPU_XRANDR (gpu);
-  MetaMonitorManager *monitor_manager = meta_gpu_get_monitor_manager (gpu);
+  MetaBackend *backend = meta_gpu_get_backend (gpu);
+  MetaMonitorManager *monitor_manager =
+    meta_backend_get_monitor_manager (backend);
   MetaMonitorManagerXrandr *monitor_manager_xrandr =
     META_MONITOR_MANAGER_XRANDR (monitor_manager);
   Display *xdisplay =
@@ -229,10 +233,10 @@ meta_gpu_xrandr_read_current (MetaGpu  *gpu,
 }
 
 MetaGpuXrandr *
-meta_gpu_xrandr_new (MetaMonitorManagerXrandr *monitor_manager_xrandr)
+meta_gpu_xrandr_new (MetaBackendX11 *backend_x11)
 {
   return g_object_new (META_TYPE_GPU_XRANDR,
-                       "monitor-manager", monitor_manager_xrandr,
+                       "backend", backend_x11,
                        NULL);
 }
 

src/backends/x11/meta-gpu-xrandr.h

@@ -26,7 +26,7 @@
 #include <X11/extensions/Xrandr.h>
 
 #include "backends/meta-gpu.h"
-#include "backends/x11/meta-monitor-manager-xrandr.h"
+#include "backends/x11/meta-backend-x11.h"
 
 #define META_TYPE_GPU_XRANDR (meta_gpu_xrandr_get_type ())
 G_DECLARE_FINAL_TYPE (MetaGpuXrandr, meta_gpu_xrandr, META, GPU_XRANDR, MetaGpu)
@@ -37,6 +37,6 @@ void meta_gpu_xrandr_get_max_screen_size (MetaGpuXrandr *gpu_xrandr,
                                           int           *max_width,
                                           int           *max_height);
 
-MetaGpuXrandr * meta_gpu_xrandr_new (MetaMonitorManagerXrandr *monitor_manager_xrandr);
+MetaGpuXrandr * meta_gpu_xrandr_new (MetaBackendX11 *backend_x11);
 
 #endif /* META_GPU_XRANDR_H */

src/backends/x11/meta-monitor-manager-xrandr.c

@@ -73,13 +73,6 @@ struct _MetaMonitorManagerXrandr
   int rr_error_base;
   gboolean has_randr15;
 
-  /*
-   * The X server deals with multiple GPUs for us, soe just see what the X
-   * server gives us as one single GPU, even though it may actually be backed
-   * by multiple.
-   */
-  MetaGpu *gpu;
-
   xcb_timestamp_t last_xrandr_set_timestamp;
 
   GHashTable *tiled_monitor_atoms;
@@ -344,6 +337,15 @@ is_output_assignment_changed (MetaOutput      *output,
   return TRUE;
 }
 
+static MetaGpu *
+meta_monitor_manager_xrandr_get_gpu (MetaMonitorManagerXrandr *manager_xrandr)
+{
+  MetaMonitorManager *manager = META_MONITOR_MANAGER (manager_xrandr);
+  MetaBackend *backend = meta_monitor_manager_get_backend (manager);
+
+  return META_GPU (meta_backend_get_gpus (backend)->data);
+}
+
 static gboolean
 is_assignments_changed (MetaMonitorManager *manager,
                         MetaCrtcInfo      **crtc_infos,
@@ -353,9 +355,10 @@ is_assignments_changed (MetaMonitorManager *manager,
 {
   MetaMonitorManagerXrandr *manager_xrandr =
     META_MONITOR_MANAGER_XRANDR (manager);
+  MetaGpu *gpu = meta_monitor_manager_xrandr_get_gpu (manager_xrandr);
   GList *l;
 
-  for (l = meta_gpu_get_crtcs (manager_xrandr->gpu); l; l = l->next)
+  for (l = meta_gpu_get_crtcs (gpu); l; l = l->next)
     {
       MetaCrtc *crtc = l->data;
 
@@ -363,7 +366,7 @@ is_assignments_changed (MetaMonitorManager *manager,
         return TRUE;
     }
 
-  for (l = meta_gpu_get_outputs (manager_xrandr->gpu); l; l = l->next)
+  for (l = meta_gpu_get_outputs (gpu); l; l = l->next)
     {
       MetaOutput *output = l->data;
 
@@ -387,6 +390,7 @@ apply_crtc_assignments (MetaMonitorManager *manager,
                         unsigned int        n_outputs)
 {
   MetaMonitorManagerXrandr *manager_xrandr = META_MONITOR_MANAGER_XRANDR (manager);
+  MetaGpu *gpu = meta_monitor_manager_xrandr_get_gpu (manager_xrandr);
   unsigned i;
   GList *l;
   int width, height, width_mm, height_mm;
@@ -448,7 +452,7 @@ apply_crtc_assignments (MetaMonitorManager *manager,
     }
 
   /* Disable CRTCs not mentioned in the list */
-  for (l = meta_gpu_get_crtcs (manager_xrandr->gpu); l; l = l->next)
+  for (l = meta_gpu_get_crtcs (gpu); l; l = l->next)
     {
       MetaCrtc *crtc = l->data;
 
@@ -568,7 +572,7 @@ apply_crtc_assignments (MetaMonitorManager *manager,
     }
 
   /* Disable outputs not mentioned in the list */
-  for (l = meta_gpu_get_outputs (manager_xrandr->gpu); l; l = l->next)
+  for (l = meta_gpu_get_outputs (gpu); l; l = l->next)
     {
       MetaOutput *output = l->data;
 
@@ -1003,8 +1007,9 @@ meta_monitor_manager_xrandr_get_max_screen_size (MetaMonitorManager *manager,
 {
   MetaMonitorManagerXrandr *manager_xrandr =
     META_MONITOR_MANAGER_XRANDR (manager);
+  MetaGpu *gpu = meta_monitor_manager_xrandr_get_gpu (manager_xrandr);
 
-  meta_gpu_xrandr_get_max_screen_size (META_GPU_XRANDR (manager_xrandr->gpu),
+  meta_gpu_xrandr_get_max_screen_size (META_GPU_XRANDR (gpu),
                                        max_width, max_height);
 
   return TRUE;
@@ -1022,13 +1027,10 @@ meta_monitor_manager_xrandr_constructed (GObject *object)
   MetaMonitorManagerXrandr *manager_xrandr =
     META_MONITOR_MANAGER_XRANDR (object);
   MetaMonitorManager *manager = META_MONITOR_MANAGER (manager_xrandr);
-  MetaBackendX11 *backend =
-    META_BACKEND_X11 (meta_monitor_manager_get_backend (manager));
+  MetaBackend *backend = meta_monitor_manager_get_backend (manager);
+  MetaBackendX11 *backend_x11 = META_BACKEND_X11 (backend);
 
-  manager_xrandr->xdisplay = meta_backend_x11_get_xdisplay (backend);
-
-  manager_xrandr->gpu = META_GPU (meta_gpu_xrandr_new (manager_xrandr));
-  meta_monitor_manager_add_gpu (manager, manager_xrandr->gpu);
+  manager_xrandr->xdisplay = meta_backend_x11_get_xdisplay (backend_x11);
 
   if (!XRRQueryExtension (manager_xrandr->xdisplay,
 			  &manager_xrandr->rr_event_base,
@@ -1068,7 +1070,6 @@ meta_monitor_manager_xrandr_finalize (GObject *object)
 {
   MetaMonitorManagerXrandr *manager_xrandr = META_MONITOR_MANAGER_XRANDR (object);
 
-  g_clear_object (&manager_xrandr->gpu);
   g_hash_table_destroy (manager_xrandr->tiled_monitor_atoms);
   g_free (manager_xrandr->supported_scales);
 
@@ -1115,6 +1116,7 @@ meta_monitor_manager_xrandr_handle_xevent (MetaMonitorManagerXrandr *manager_xra
 					   XEvent                   *event)
 {
   MetaMonitorManager *manager = META_MONITOR_MANAGER (manager_xrandr);
+  MetaGpu *gpu = meta_monitor_manager_xrandr_get_gpu (manager_xrandr);
   MetaGpuXrandr *gpu_xrandr;
   XRRScreenResources *resources;
   gboolean is_hotplug;
@@ -1127,7 +1129,7 @@ meta_monitor_manager_xrandr_handle_xevent (MetaMonitorManagerXrandr *manager_xra
 
   meta_monitor_manager_read_current_state (manager);
 
-  gpu_xrandr = META_GPU_XRANDR (manager_xrandr->gpu);
+  gpu_xrandr = META_GPU_XRANDR (gpu);
   resources = meta_gpu_xrandr_get_resources (gpu_xrandr);
 
   is_hotplug = resources->timestamp < resources->configTimestamp;

src/backends/x11/meta-output-xrandr.c

@@ -41,6 +41,7 @@
 #include <X11/Xlib-xcb.h>
 #include <xcb/randr.h>
 
+#include "backends/meta-backend-private.h"
 #include "backends/meta-crtc.h"
 #include "backends/x11/meta-monitor-manager-xrandr.h"
 #include "meta/util.h"
@@ -49,7 +50,9 @@ static Display *
 xdisplay_from_output (MetaOutput *output)
 {
   MetaGpu *gpu = meta_output_get_gpu (output);
-  MetaMonitorManager *monitor_manager = meta_gpu_get_monitor_manager (gpu);
+  MetaBackend *backend = meta_gpu_get_backend (gpu);
+  MetaMonitorManager *monitor_manager =
+    meta_backend_get_monitor_manager (backend);
   MetaMonitorManagerXrandr *monitor_manager_xrandr =
     META_MONITOR_MANAGER_XRANDR (monitor_manager);
 
@@ -643,7 +646,9 @@ static void
 output_get_tile_info (MetaOutput *output)
 {
   MetaGpu *gpu = meta_output_get_gpu (output);
-  MetaMonitorManager *monitor_manager = meta_gpu_get_monitor_manager (gpu);
+  MetaBackend *backend = meta_gpu_get_backend (gpu);
+  MetaMonitorManager *monitor_manager =
+    meta_backend_get_monitor_manager (backend);
   MetaMonitorManagerXrandr *monitor_manager_xrandr =
     META_MONITOR_MANAGER_XRANDR (monitor_manager);
   Display *xdisplay = xdisplay_from_output (output);

src/backends/x11/nested/meta-backend-x11-nested.c

@@ -28,8 +28,13 @@
 
 #include "wayland/meta-wayland.h"
 
-G_DEFINE_TYPE (MetaBackendX11Nested, meta_backend_x11_nested,
-               META_TYPE_BACKEND_X11)
+typedef struct _MetaBackendX11NestedPrivate
+{
+  MetaGpu *gpu;
+} MetaBackendX11NestedPrivate;
+
+G_DEFINE_TYPE_WITH_PRIVATE (MetaBackendX11Nested, meta_backend_x11_nested,
+                            META_TYPE_BACKEND_X11)
 
 static MetaRenderer *
 meta_backend_x11_nested_create_renderer (MetaBackend *backend,
@@ -182,6 +187,32 @@ meta_backend_x11_nested_translate_device_event (MetaBackendX11 *x11,
   g_assert (device_event->event == meta_backend_x11_get_xwindow (x11));
 }
 
+static void
+meta_backend_x11_nested_real_init_gpus (MetaBackendX11Nested *backend_x11_nested)
+{
+  MetaBackendX11NestedPrivate *priv =
+    meta_backend_x11_nested_get_instance_private (backend_x11_nested);
+
+  priv->gpu = g_object_new (META_TYPE_GPU_DUMMY,
+                            "backend", backend_x11_nested,
+                            NULL);
+  meta_backend_add_gpu (META_BACKEND (backend_x11_nested), priv->gpu);
+}
+
+static void
+meta_backend_x11_nested_constructed (GObject *object)
+{
+  MetaBackendX11Nested *backend_x11_nested = META_BACKEND_X11_NESTED (object);
+  MetaBackendX11NestedClass *backend_x11_nested_class =
+    META_BACKEND_X11_NESTED_GET_CLASS (backend_x11_nested);
+  GObjectClass *parent_class =
+    G_OBJECT_CLASS (meta_backend_x11_nested_parent_class);
+
+  parent_class->constructed (object);
+
+  backend_x11_nested_class->init_gpus (backend_x11_nested);
+}
+
 static void
 meta_backend_x11_nested_init (MetaBackendX11Nested *backend_x11_nested)
 {
@@ -190,9 +221,12 @@ meta_backend_x11_nested_init (MetaBackendX11Nested *backend_x11_nested)
 static void
 meta_backend_x11_nested_class_init (MetaBackendX11NestedClass *klass)
 {
+  GObjectClass *object_class = G_OBJECT_CLASS (klass);
   MetaBackendClass *backend_class = META_BACKEND_CLASS (klass);
   MetaBackendX11Class *backend_x11_class = META_BACKEND_X11_CLASS (klass);
 
+  object_class->constructed = meta_backend_x11_nested_constructed;
+
   backend_class->create_renderer = meta_backend_x11_nested_create_renderer;
   backend_class->create_monitor_manager = meta_backend_x11_nested_create_monitor_manager;
   backend_class->create_cursor_renderer = meta_backend_x11_nested_create_cursor_renderer;
@@ -205,4 +239,6 @@ meta_backend_x11_nested_class_init (MetaBackendX11NestedClass *klass)
 
   backend_x11_class->handle_host_xevent = meta_backend_x11_nested_handle_host_xevent;
   backend_x11_class->translate_device_event = meta_backend_x11_nested_translate_device_event;
+
+  klass->init_gpus = meta_backend_x11_nested_real_init_gpus;
 }

src/backends/x11/nested/meta-backend-x11-nested.h

@@ -33,6 +33,8 @@ G_DECLARE_DERIVABLE_TYPE (MetaBackendX11Nested, meta_backend_x11_nested,
 struct _MetaBackendX11NestedClass
 {
   MetaBackendX11Class parent_class;
+
+  void (* init_gpus) (MetaBackendX11Nested *backend_x11_nested);
 };
 
 #endif /* META_BACKEND_X11_NESTED_H */