alsa_sound: Add support for custom LPA buffer size
* On msm8930, during playback over A2DP with DSP Manager effects enabled,
there's a lot of stuttering with the default buffer size. Stock kernel
used a buffer size of 32, but that caused no audio at all in CM because
of mismatch in buffer size between kernel and user space. So up until
now I've been using a buffer size of 256 to get audio working at all,
but unfortunately it causes stuttering as mentioned. Hence add support
for a custom buffer size so we can revert to stock value used in kernel,
and enjoy no stuttering.
Change-Id: I29113cee46d0adcc72a8c9c830e4c15d9fdd43dc
diff --git a/alsa_sound/AudioSessionOut.cpp b/alsa_sound/AudioSessionOut.cpp
index 0e71ec5..01c9d88 100644
--- a/alsa_sound/AudioSessionOut.cpp
+++ b/alsa_sound/AudioSessionOut.cpp
@@ -59,7 +59,10 @@
#define NUM_FDS 2
#define KILL_EVENT_THREAD 1
#define BUFFER_COUNT 4
-#define LPA_BUFFER_SIZE 256*1024
+#ifndef LPA_DEFAULT_BUFFER_SIZE
+#define LPA_DEFAULT_BUFFER_SIZE 256
+#endif
+#define LPA_BUFFER_SIZE LPA_DEFAULT_BUFFER_SIZE*1024
#define TUNNEL_BUFFER_SIZE 240*1024
#define TUNNEL_METADATA_SIZE 64
#define MONO_CHANNEL_MODE 1