* Creating a Desktop can fail, in which case the app_server should not return B_OK,

and an invalid desktop message port...
* Desktop::Init() now checks if VirtualScreen::fHWInterface is valid, and exits
  if not. This can happen if you don't have a graphics driver, and turn on on-screen
  debug mode in the boot loader (such that you already see the messages from the
  boot loader).


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@24371 a95241bf-73f2-0310-859d-f6bbb57e9c96

src/servers/app/AppServer.cpp

@@ -188,8 +188,12 @@ AppServer::_DispatchMessage(int32 code, BPrivate::LinkReceiver& msg)
 			}
 
 			BPrivate::LinkSender reply(replyPort);
-			reply.StartMessage(B_OK);
+			if (desktop != NULL) {
-			reply.Attach<port_id>(desktop->MessagePort());
+				reply.StartMessage(B_OK);
+				reply.Attach<port_id>(desktop->MessagePort());
+			} else
+				reply.StartMessage(B_ERROR);
+
 			reply.Flush();
 			break;
 		}

src/servers/app/Desktop.cpp

@@ -385,6 +385,11 @@ Desktop::Init()
 	// TODO: temporary workaround, fActiveScreen will be removed
 	fActiveScreen = fVirtualScreen.ScreenAt(0);
 
+	if (fVirtualScreen.HWInterface() == NULL) {
+		debug_printf("Could not initialize graphics output. Exiting.\n");
+		return B_ERROR;
+	}
+
 	fVirtualScreen.HWInterface()->MoveCursorTo(fVirtualScreen.Frame().Width() / 2,
 		fVirtualScreen.Frame().Height() / 2);