[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, 4 insertions, 2 deletions

diff --git a/sound/core/pcm_native.c b/sound/core/pcm_native.c
index 37b4b10850ae..66e24b5da469 100644
--- a/sound/core/pcm_native.c
+++ b/sound/core/pcm_native.c
@@ -1310,7 +1310,8 @@ static int snd_pcm_pre_prepare(struct snd_pcm_substream *substream,
                                int f_flags)
 {
         struct snd_pcm_runtime *runtime = substream->runtime;
-        if (runtime->status->state == SNDRV_PCM_STATE_OPEN)
+        if (runtime->status->state == SNDRV_PCM_STATE_OPEN ||
+            runtime->status->state == SNDRV_PCM_STATE_DISCONNECTED)
                 return -EBADFD;
         if (snd_pcm_running(substream))
                 return -EBUSY;
@@ -1568,7 +1569,8 @@ static int snd_pcm_drop(struct snd_pcm_substream *substream)
         runtime = substream->runtime;
         card = substream->pcm->card;
 
-        if (runtime->status->state == SNDRV_PCM_STATE_OPEN)
+        if (runtime->status->state == SNDRV_PCM_STATE_OPEN ||
+            runtime->status->state == SNDRV_PCM_STATE_DISCONNECTED)
                 return -EBADFD;
 
         snd_power_lock(card);