ALSA: line6: Fix -EBUSY error during active monitoring

When a monitor stream is active, the next PCM stream access results in
EBUSY error because of the check in line6_stream_start().  Fix this by
just skipping the submission of pending URBs when the stream is
already running instead.

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=101431
Cc: <stable@vger.kernel.org> # v4.0+
Signed-off-by: Takashi Iwai <tiwai@suse.de>

diff --git a/sound/usb/line6/pcm.c b/sound/usb/line6/pcm.c
index 8461d6b..204cc07 100644 (file)
--- a/sound/usb/line6/pcm.c
+++ b/sound/usb/line6/pcm.c
@@ -186,12 +186,8 @@ static int line6_stream_start(struct snd_line6_pcm *line6pcm, int direction,
        int ret = 0;
 
        spin_lock_irqsave(&pstr->lock, flags);
-       if (!test_and_set_bit(type, &pstr->running)) {
-               if (pstr->active_urbs || pstr->unlink_urbs) {
-                       ret = -EBUSY;
-                       goto error;
-               }
-
+       if (!test_and_set_bit(type, &pstr->running) &&
+           !(pstr->active_urbs || pstr->unlink_urbs)) {
                pstr->count = 0;
                /* Submit all currently available URBs */
                if (direction == SNDRV_PCM_STREAM_PLAYBACK)
@@ -199,7 +195,6 @@ static int line6_stream_start(struct snd_line6_pcm *line6pcm, int direction,
                else
                        ret = line6_submit_audio_in_all_urbs(line6pcm);
        }
- error:
        if (ret < 0)
                clear_bit(type, &pstr->running);
        spin_unlock_irqrestore(&pstr->lock, flags);