[ALSA] Fix hang-up at disconnection of usb-audio

Fix hang-up at disconnection of usb-audio devices while accessing PCM.
Don't handle PCM operations any more after shutdown flag is set.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@suse.cz>

1 files changed, 2 insertions, 1 deletions

diff --git a/sound/core/oss/pcm_oss.c b/sound/core/oss/pcm_oss.c
index 505b23ec4058..e0821eb3d851 100644
--- a/sound/core/oss/pcm_oss.c
+++ b/sound/core/oss/pcm_oss.c
@@ -2359,7 +2359,8 @@ static int snd_pcm_oss_release(struct inode *inode, struct file *file)
                 substream = pcm_oss_file->streams[SNDRV_PCM_STREAM_CAPTURE];
         snd_assert(substream != NULL, return -ENXIO);
         pcm = substream->pcm;
-        snd_pcm_oss_sync(pcm_oss_file);
+        if (!pcm->card->shutdown)
+                snd_pcm_oss_sync(pcm_oss_file);
         mutex_lock(&pcm->open_mutex);
         snd_pcm_oss_release_file(pcm_oss_file);
         mutex_unlock(&pcm->open_mutex);