From mboxrd@z Thu Jan  1 00:00:00 1970
From: Clemens Ladisch <clemens@ladisch.de>
Subject: Re: [alsa-devel] [PATCH 24/44] fireworks: Add MIDI interface
Date: Thu, 03 Apr 2014 23:20:03 +0200
Message-ID: <533DD083.10506@ladisch.de>
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To: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Cc: tiwai@suse.de, alsa-devel@alsa-project.org, linux1394-devel@lists.sourceforge.net, ffado-devel@lists.sf.net, perex@perex.cz
List-Id: alsa-devel@alsa-project.org

Takashi Sakamoto wrote:
> This commit adds a functionality to capture/playback MIDI messages.
>
> When no AMDTP streams are running, this driver starts AMDTP stream for MIDI
> stream at current sampling rate.
>
> +++ b/sound/firewire/fireworks/fireworks_midi.c
> +static int midi_capture_open(struct snd_rawmidi_substream *substream)
> +{
> +	struct snd_efw *efw = substream->rmidi->private_data;
> +
> +	efw->capture_substreams++;

The MIDI .open callback is not synchronized with the PCM callbacks;
this might race and must be protected with a mutex.


Regards,
Clemens

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