ALSA: firewire-lib: schedule work again when MIDI substream has rest of MIDI messages

Currently, when two MIDI trigger callbacks can be called immediately,
transactions for the second MIDI messages can be postpone till next trigger
callback. This is not good for real-time message transmission.

This commit schedules work again at response handling callback if the
MIDI substream still includes untransferred MIDI messages.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

diff --git a/sound/firewire/lib.c b/sound/firewire/lib.c
index ddc3e88ee0d197c668fdfe620f3eb43989db9f6e..3e9afd7d402ca1d5832d45a3f01cd251e3aeb68c 100644 (file)
--- a/sound/firewire/lib.c
+++ b/sound/firewire/lib.c
@@ -78,6 +78,9 @@ static void async_midi_port_callback(struct fw_card *card, int rcode,
                snd_rawmidi_transmit_ack(substream, port->consume_bytes);
 
        port->idling = true;
+
+       if (!snd_rawmidi_transmit_empty(substream))
+               schedule_work(&port->work);
 }
 
 static void midi_port_work(struct work_struct *work)