Only return POLLIN if keyboard event added a character to the buffer

src/main.rs

@@ -114,10 +114,12 @@ fn process_keyboard_data() {
             pc_keyboard::DecodedKey::RawKey(_) => (),
             pc_keyboard::DecodedKey::Unicode(ch) => KEYPRESS_BUF.lock().push_back(ch),
         }
+        if !KEYPRESS_BUF.lock().is_empty() {
             for mut poll in POLLS.lock().drain(..) {
                 poll.reply(PollEvents::POLLIN);
             }
         }
+    }
 }
 
 fn main() {