drm-buffer/gbm: Support both surface and standalone buffers

Surface buffers are created with meta_drm_buffer_new_acquire(), taking a
gbm_surface acquiring the gbm itself, and meta_drm_buffer_new_take()
that takes over ownership of a passed gbm_bo.

Original Mutter commit: https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/798/diffs?commit_id=282aada13a5d744dd29eedf3255b6a9f6d0e370c

Author: Sunderland93

src/backends/native/meta-drm-buffer-gbm.c

@@ -53,22 +53,12 @@ meta_drm_buffer_gbm_get_bo (MetaDrmBufferGbm *buffer_gbm)
 }
 
 static gboolean
-acquire_swapped_buffer (MetaDrmBufferGbm  *buffer_gbm,
-                        gboolean           use_modifiers,
-                        GError           **error)
+init_fb_id (MetaDrmBufferGbm  *buffer_gbm,
+            struct gbm_bo     *bo,
+            gboolean           use_modifiers,
+            GError           **error)
 {
   MetaGpuKmsFBArgs fb_args = { 0, };
-  struct gbm_bo *bo;
-
-  bo = gbm_surface_lock_front_buffer (buffer_gbm->surface);
-  if (!bo)
-    {
-      g_set_error (error,
-                   G_IO_ERROR,
-                   G_IO_ERROR_FAILED,
-                   "gbm_surface_lock_front_buffer failed");
-      return FALSE;
-    }
 
   if (gbm_bo_get_handle_for_plane (bo, 0).s32 == -1)
     {
@@ -99,37 +89,71 @@ acquire_swapped_buffer (MetaDrmBufferGbm  *buffer_gbm,
                             use_modifiers,
                             &fb_args,
                             &buffer_gbm->fb_id, error))
+    return FALSE;
+  return TRUE;
+}
+
+static gboolean
+lock_front_buffer (MetaDrmBufferGbm  *buffer_gbm,
+                   gboolean           use_modifiers,
+                   GError           **error)
+{
+  buffer_gbm->bo = gbm_surface_lock_front_buffer (buffer_gbm->surface);
+  if (!buffer_gbm->bo)
     {
-      gbm_surface_release_buffer (buffer_gbm->surface, bo);
+      g_set_error (error,
+                   G_IO_ERROR,
+                   G_IO_ERROR_FAILED,
+                   "gbm_surface_lock_front_buffer failed");
       return FALSE;
     }
+  return init_fb_id (buffer_gbm, buffer_gbm->bo, use_modifiers, error);
+}
 
-  buffer_gbm->bo = bo;
+MetaDrmBufferGbm *
+meta_drm_buffer_gbm_new_lock_front (MetaGpuKms          *gpu_kms,
+                                    struct gbm_surface  *gbm_surface,
+                                    gboolean             use_modifiers,
+                                    GError             **error)
+{
+  MetaDrmBufferGbm *buffer_gbm;
 
-  return TRUE;
+  buffer_gbm = g_object_new (META_TYPE_DRM_BUFFER_GBM, NULL);
+  buffer_gbm->gpu_kms = gpu_kms;
+  buffer_gbm->surface = gbm_surface;
+
+  if (!lock_front_buffer (buffer_gbm, use_modifiers, error))
+    {
+      g_object_unref (buffer_gbm);
+      return NULL;
+    }
+
+  return buffer_gbm;
 }
 
 MetaDrmBufferGbm *
-meta_drm_buffer_gbm_new (MetaGpuKms          *gpu_kms,
-                         struct gbm_surface  *gbm_surface,
-                         gboolean             use_modifiers,
-                         GError             **error)
+meta_drm_buffer_gbm_new_take (MetaGpuKms     *gpu_kms,
+                              struct gbm_bo  *bo,
+                              gboolean        use_modifiers,
+                              GError        **error)
 {
   MetaDrmBufferGbm *buffer_gbm;
 
   buffer_gbm = g_object_new (META_TYPE_DRM_BUFFER_GBM, NULL);
   buffer_gbm->gpu_kms = gpu_kms;
-  buffer_gbm->surface = gbm_surface;
 
-  if (!acquire_swapped_buffer (buffer_gbm, use_modifiers, error))
+  if (!init_fb_id (buffer_gbm, bo, use_modifiers, error))
     {
       g_object_unref (buffer_gbm);
       return NULL;
     }
 
+  buffer_gbm->bo = bo;
+
   return buffer_gbm;
 }
 
+
 static uint32_t
 meta_drm_buffer_gbm_get_fb_id (MetaDrmBuffer *buffer)
 {
@@ -150,7 +174,12 @@ meta_drm_buffer_gbm_finalize (GObject *object)
     }
 
   if (buffer_gbm->bo)
-    gbm_surface_release_buffer (buffer_gbm->surface, buffer_gbm->bo);
+    {
+      if (buffer_gbm->surface)
+        gbm_surface_release_buffer (buffer_gbm->surface, buffer_gbm->bo);
+      else
+        gbm_bo_destroy (buffer_gbm->bo);
+    }
 
   G_OBJECT_CLASS (meta_drm_buffer_gbm_parent_class)->finalize (object);
 }

src/backends/native/meta-drm-buffer-gbm.h

@@ -33,10 +33,16 @@ G_DECLARE_FINAL_TYPE (MetaDrmBufferGbm,
                       META, DRM_BUFFER_GBM,
                       MetaDrmBuffer)
 
-MetaDrmBufferGbm * meta_drm_buffer_gbm_new (MetaGpuKms          *gpu_kms,
-                                            struct gbm_surface  *gbm_surface,
-                                            gboolean             use_modifiers,
-                                            GError             **error);
+MetaDrmBufferGbm * meta_drm_buffer_gbm_new_lock_front (MetaGpuKms          *gpu_kms,
+                                                       struct gbm_surface  *gbm_surface,
+                                                       gboolean             use_modifiers,
+                                                       GError             **error);
+
+
+MetaDrmBufferGbm * meta_drm_buffer_gbm_new_take (MetaGpuKms     *gpu_kms,
+                                                 struct gbm_bo  *gbm_bo,
+                                                 gboolean        use_modifiers,
+                                                 GError        **error);
 
 struct gbm_bo * meta_drm_buffer_gbm_get_bo (MetaDrmBufferGbm *buffer_gbm);
 

src/backends/native/meta-renderer-native.c

@@ -1621,13 +1621,14 @@ copy_shared_framebuffer_gpu (CoglOnscreen                        *onscreen,
       return;
     }
 
-  buffer_gbm = meta_drm_buffer_gbm_new (secondary_gpu_state->gpu_kms,
+  buffer_gbm =
+    meta_drm_buffer_gbm_new_lock_front (secondary_gpu_state->gpu_kms,
                                         secondary_gpu_state->gbm.surface,
                                         renderer_native->use_modifiers,
                                         &error);
   if (!buffer_gbm)
     {
-      g_warning ("meta_drm_buffer_gbm_new failed: %s",
+      g_warning ("meta_drm_buffer_gbm_new_lock_front failed: %s",
                  error->message);
       g_error_free (error);
       return;
@@ -2113,13 +2114,14 @@ meta_onscreen_native_swap_buffers_with_damage (CoglOnscreen *onscreen,
       g_warn_if_fail (onscreen_native->gbm.next_fb == NULL);
       g_clear_object (&onscreen_native->gbm.next_fb);
 
-      buffer_gbm = meta_drm_buffer_gbm_new (render_gpu,
+      buffer_gbm =
+      meta_drm_buffer_gbm_new_lock_front (render_gpu,
                                             onscreen_native->gbm.surface,
                                             renderer_native->use_modifiers,
                                             &error);
       if (!buffer_gbm)
         {
-          g_warning ("meta_drm_buffer_gbm_new failed: %s",
+          g_warning ("meta_drm_buffer_gbm_new_lock_front failed: %s",
                      error->message);
           return;
         }