keyboard: use fallback layout if failing to load

src/hid/x11.rs

@@ -10,6 +10,11 @@ pub fn get_keymap_x11() -> anyhow::Result<XkbKeymap> {
 
     let (conn, _) = xcb::Connection::connect(None)?;
     let device_id = get_core_keyboard_device_id(&conn);
+    if device_id == -1 {
+        return Err(anyhow::anyhow!(
+            "get_core_keyboard_device_id returned -1. Check your XKB installation."
+        ));
+    }
     let keymap = keymap_new_from_device(&context, &conn, device_id, xkb::KEYMAP_COMPILE_NO_FLAGS);
 
     Ok(XkbKeymap { context, keymap })