[PATCH 6/7] ALSA: pcm: Block the release until the system resume finishes

[Takashi Iwai <tiwai@suse.de>]

The normal PCM operations are already blocked during the card power
off state in the PCM common ioctl handler, but the release isn't
covered.  As the PCM stream release may also access the hardware,
let's block the release until the card power turns on.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
---
 sound/core/pcm_native.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/sound/core/pcm_native.c b/sound/core/pcm_native.c
index 8dbe86cf2e4f..3c6ba0dc2970 100644
--- a/sound/core/pcm_native.c
+++ b/sound/core/pcm_native.c
@@ -2799,6 +2799,10 @@ static int snd_pcm_release(struct inode *inode, struct file *file)
 	if (snd_BUG_ON(!substream))
 		return -ENXIO;
 	pcm = substream->pcm;
+
+	/* block until the device gets woken up as it may touch the hardware */
+	snd_power_wait(pcm->card, SNDRV_CTL_POWER_D0);
+
 	mutex_lock(&pcm->open_mutex);
 	snd_pcm_release_substream(substream);
 	kfree(pcm_file);
-- 
2.26.2