hosted: Improve buffer underrun handling in the ALSA driver

 * Bump internal mix buffer size by 4x, to 1K frames (matching ALSA period)
 * Handle an underrun that occurs when filling the audio buffer
 * Log underruns and make them available in the debug info

Change-Id: I28d56dd35d88851fa167ad92368a5882937a758f

1 files changed, 8 insertions, 7 deletions

diff --git a/firmware/target/hosted/pcm-alsa.h b/firmware/target/hosted/pcm-alsa.h
index 1392593c0c..4c0b0d0b9d 100644
--- a/firmware/target/hosted/pcm-alsa.h
+++ b/firmware/target/hosted/pcm-alsa.h
@@ -1,10 +1,10 @@
 /***************************************************************************
- *             __________               __   ___.                  
- *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___  
- *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /  
- *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <   
- *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \  
- *                     \/            \/     \/    \/            \/ 
+ *             __________               __   ___.
+ *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
+ *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
+ *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
+ *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
+ *                     \/            \/     \/    \/            \/
  *
  * Copyright (C) 2016 Amaury Pouly
  *
@@ -34,6 +34,7 @@ void pcm_alsa_set_playback_device(const char *device);
 void pcm_alsa_set_capture_device(const char *device);
 #endif
 
-int pcm_alsa_get_rate(void);
+unsigned int pcm_alsa_get_rate(void);
+unsigned int pcm_alsa_get_xruns(void);
 
 #endif /* __PCM_ALSA_RB_H__ */