If a driver does not supply a drain operation for outputs, a default code path will execute msleep(50). Especially for a virtual midi device this severely limmits the throughput.

This implementation for the virtual midi driver simply flushes the output workqueue.

Signed-off-by: Stefan Sauer st_kost@gmx.de --- sound/core/seq/seq_virmidi.c | 11 +++++++++++ 1 file changed, 11 insertions(+)

diff --git a/sound/core/seq/seq_virmidi.c b/sound/core/seq/seq_virmidi.c index 4abc38c70cae..f5cae49500c8 100644 --- a/sound/core/seq/seq_virmidi.c +++ b/sound/core/seq/seq_virmidi.c @@ -262,6 +262,16 @@ static int snd_virmidi_output_close(struct snd_rawmidi_substream *substream) return 0; }

+/* + * drain output work queue + */ +static void snd_virmidi_output_drain(struct snd_rawmidi_substream *substream) +{ + struct snd_virmidi *vmidi = substream->runtime->private_data; + + flush_work(&vmidi->output_work); +} + /* * subscribe callback - allow output to rawmidi device */ @@ -336,6 +346,7 @@ static const struct snd_rawmidi_ops snd_virmidi_output_ops = { .open = snd_virmidi_output_open, .close = snd_virmidi_output_close, .trigger = snd_virmidi_output_trigger, + .drain = snd_virmidi_output_drain, };

/* -- 2.34.1