From ba18ca2b8e18146228ff36b50f0c9a3f5c5bd1b5 Mon Sep 17 00:00:00 2001
From: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Date: Sun, 7 Jul 2019 14:20:11 +0900
Subject: [PATCH] firewire-motu: fix wrong reference count for stream
functionality at error path of rawmidi interface
In IEC 61883-6, several types of sampling data can be multiplexed into
payload of common isochronous packet (CIP). For typical audio and music
units, PCM samples and MIDI messages are multiplexed into one packet
streaming.
ALSA firewire-motu driver allows applications of rawmidi interface to
start packet streaming for transmission of MIDI messages. However at
error path, the reference count of stream functionality is not operated
correctly. This can brings a bug that packet streaming is not stopped
when all referrers release the count.
This commit fixes the bug.
Fixes: 8edc56ec8f14 ("ALSA: firewire-motu: reserve/release isochronous resources in pcm.hw_params/hw_free callbacks")
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
---
sound/firewire/motu/motu-midi.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/sound/firewire/motu/motu-midi.c b/sound/firewire/motu/motu-midi.c
index 4520c0060b837..5c77e417c627e 100644
--- a/sound/firewire/motu/motu-midi.c
+++ b/sound/firewire/motu/motu-midi.c
@@ -22,6 +22,8 @@ static int midi_open(struct snd_rawmidi_substream *substream)
if (err >= 0) {
++motu->substreams_counter;
err = snd_motu_stream_start_duplex(motu);
+ if (err < 0)
+ --motu->substreams_counter;
}
mutex_unlock(&motu->mutex);
--
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