ALSA: compress: fix drain calls blocking other compress functions

The drain and drain_notify callback were blocked by low level driver untill the
draining was complete. Due to this being invoked with big fat mutex held, others
ops like reading timestamp, calling pause, drop were blocked.

So to fix this we add a new snd_compr_drain_notify() API. This would be required
to be invoked by low level driver when drain or partial drain has been completed
by the DSP. Thus we make the drain and partial_drain callback as non blocking
and driver returns immediately after notifying DSP.
The waiting is done while relasing the lock so that other ops can go ahead.

Signed-off-by: Vinod Koul <vinod.koul@intel.com>
CC: stable@vger.kernel.org
Signed-off-by: Takashi Iwai <tiwai@suse.de>

1 files changed, 12 insertions, 0 deletions

diff --git a/include/sound/compress_driver.h b/include/sound/compress_driver.h
index 9031a26249b5..175ab3237b58 100644
--- a/include/sound/compress_driver.h
+++ b/include/sound/compress_driver.h
@@ -48,6 +48,8 @@ struct snd_compr_ops;
  *      the ring buffer
  * @total_bytes_transferred: cumulative bytes transferred by offload DSP
  * @sleep: poll sleep
+ * @wait: drain wait queue
+ * @drain_wake: condition for drain wake
  */
 struct snd_compr_runtime {
         snd_pcm_state_t state;
@@ -59,6 +61,8 @@ struct snd_compr_runtime {
         u64 total_bytes_available;
         u64 total_bytes_transferred;
         wait_queue_head_t sleep;
+        wait_queue_head_t wait;
+        unsigned int drain_wake;
         void *private_data;
 };
 
@@ -171,4 +175,12 @@ static inline void snd_compr_fragment_elapsed(struct snd_compr_stream *stream)
         wake_up(&stream->runtime->sleep);
 }
 
+static inline void snd_compr_drain_notify(struct snd_compr_stream *stream)
+{
+        snd_BUG_ON(!stream);
+
+        stream->runtime->drain_wake = 1;
+        wake_up(&stream->runtime->wait);
+}
+
 #endif