From 7560ee032b3f87fa5c4f03e99a064c6cd326951e Mon Sep 17 00:00:00 2001 From: Stefan Sauer Date: Thu, 6 Jan 2022 13:41:45 +0100 Subject: [PATCH] ALSA: seq: virmidi: Add a drain operation 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 Link: https://lore.kernel.org/r/20220106124145.17254-1-st_kost@gmx.de Signed-off-by: Takashi Iwai --- 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 4abc38c..f5cae49 100644 --- a/sound/core/seq/seq_virmidi.c +++ b/sound/core/seq/seq_virmidi.c @@ -263,6 +263,16 @@ static int snd_virmidi_output_close(struct snd_rawmidi_substream *substream) } /* + * 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 */ static int snd_virmidi_subscribe(void *private_data, @@ -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, }; /* -- 2.7.4