[drm] bail if not in 24bpp color mode

Some server hardware gets initialized into 8bpp mode to
conserve memory.  We can't work in that mode, so we now
check for it and back early.

diff --git a/src/plugins/renderers/drm/plugin.c b/src/plugins/renderers/drm/plugin.c
index 34a7a3899b7f7538e01e0e5200ad29aa73d75108..bf70f97cca7463efba7257b499a213d6d11de0cd 100644 (file)
--- a/src/plugins/renderers/drm/plugin.c
+++ b/src/plugins/renderers/drm/plugin.c
@@ -766,6 +766,29 @@ get_index_of_active_mode (ply_renderer_backend_t *backend,
   return find_index_of_mode (backend, connector, &controller->mode);
 }
 
+static bool
+buffer_has_reasonable_color_depth (ply_renderer_backend_t *backend,
+                                   uint32_t                buffer_id)
+{
+
+  unsigned int color_depth;
+  bool has_reasonable_color_depth;
+
+  if (!backend->driver_interface->fetch_buffer (backend->driver,
+                                                buffer_id,
+                                                NULL, NULL, NULL, &color_depth))
+    return false;
+
+  if (color_depth == 24 || color_depth == 32)
+    has_reasonable_color_depth = true;
+  else
+    has_reasonable_color_depth = false;
+
+  backend->driver_interface->destroy_buffer (backend->driver, buffer_id);
+
+  return has_reasonable_color_depth;
+}
+
 static bool
 create_heads_for_active_connectors (ply_renderer_backend_t *backend)
 {
@@ -833,6 +856,13 @@ create_heads_for_active_connectors (ply_renderer_backend_t *backend)
       console_buffer_id = controller->buffer_id;
       drmModeFreeCrtc (controller);
 
+      if (!buffer_has_reasonable_color_depth (backend, console_buffer_id))
+        {
+          ply_trace ("frame buffer console doesn't have usable color depth");
+          free_heads (backend);
+          return false;
+        }
+
       head = ply_renderer_head_new (backend, connector, connector_mode_index,
                                     encoder_id, controller_id,
                                     console_buffer_id);