I think there should be a 'break' after line 1063

[kelehaishiyao]

while (schannel->state == SPEECH_CHANNEL_CLOSED) {
	if (switch_thread_cond_timedwait(schannel->cond, schannel->mutex, SPEECH_CHANNEL_TIMEOUT_USEC) == SWITCH_STATUS_TIMEOUT && !warned) {
		warned = 1;
		switch_log_printf(SWITCH_CHANNEL_UUID_LOG(schannel->session_uuid), SWITCH_LOG_WARNING, "(%s) MRCP session has not opened after %d ms\n", schannel->name, SPEECH_CHANNEL_TIMEOUT_USEC / (1000));
                    break; // <----------------------------------------------------
	}
}

[seven1240]

I think it is by design, do you hit a problem when it runs forever? what if you comment out warned = 1?