Commit 7560ee03 authored by Stefan Sauer's avatar Stefan Sauer Committed by Takashi Iwai
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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: default avatarStefan Sauer <st_kost@gmx.de>
Link: https://lore.kernel.org/r/20220106124145.17254-1-st_kost@gmx.de


Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
parent b81e9e5c

sound/core/seq/seq_virmidi.c

+11 −0
Original line number Diff line number Diff line
@@ -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,

};



/*