[PATCH] ALSA: seq: virmidi: Add a drain operation

[Geraldo Nascimento]

On Wed, Jan 05, 2022 at 09:47:17PM +0100, Stefan Sauer wrote:
> 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 at gmail.com>

Hi, Stefan,

Thanks for the patch!

However it seems you forgot to Cc: Takashi Iwai.

Cc:ing him now so he takes notice.

Thank you,
Geraldo Nascimento
> ---
>  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
>