ALSA: firewire-digi00x: fix wrong reference count for stream functionality at error...

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-digi00x 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: 98d8e1b42e74 ("ALSA: firewire-digi00x: 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>

diff --git a/sound/firewire/digi00x/digi00x-midi.c b/sound/firewire/digi00x/digi00x-midi.c
index ca06ad318ed6d334b5f32d1634d9e3fc1498fbbe..0563701141b821fe4df86ed2153443cb93fe91dc 100644 (file)
--- a/sound/firewire/digi00x/digi00x-midi.c
+++ b/sound/firewire/digi00x/digi00x-midi.c
@@ -22,6 +22,8 @@ static int midi_open(struct snd_rawmidi_substream *substream)
        if (err >= 0) {
                ++dg00x->substreams_counter;
                err = snd_dg00x_stream_start_duplex(dg00x);
+               if (err < 0)
+                       --dg00x->substreams_counter;
        }
        mutex_unlock(&dg00x->mutex);
        if (err < 0)