Function write_to_hid_interface

app/hid/write.py:26–41

(hid_path, buffer)

def write_to_hid_interface(hid_path, buffer):
    # Avoid an unnecessary string formatting call in a write that requires low
    # latency.
    if logger.getEffectiveLevel() == logging.DEBUG:
        logger.debug_sensitive('writing to HID interface %s: %s', hid_path,
                               ' '.join([f'{x:#04x}' for x in buffer]))
    # Writes can hang, for example, when TinyPilot is attempting to write to the
    # mouse interface, but the target system has no GUI. To avoid locking up the
    # main server process, perform the HID interface I/O in a separate process.
    try:
        execute.with_timeout(_write_to_hid_interface_immediately,
                             args=(hid_path, buffer),
                             timeout_in_seconds=0.5)
    except TimeoutError as e:
        raise WriteError(f'Failed to write to HID interface: {hid_path}. '
                         'Is USB cable connected?') from e