commit 8861338c2a520669a870ee5f3e0c740e438c99bc
author SathishKumar Mani <smani@codeaurora.org> Mon Aug 13 18:40:18 2012 -0700
committer Iliyan Malchev <malchev@google.com> Wed Sep 12 22:45:33 2012 -0700
tree 16959e8103737b10c34b6b438a07078101481ea5
parent 94de74c9450130f9dd01972414b18cb358062876

alsa_sound: add support for low latency playback and recording

b/6865729

- Add deep buffer output in config file
- Configure deep buffer output if flag
  AUDIO_OUTPUT_FLAG_DEEP_BUFFER is set,
  otherwise configure low latency output.
- Add support for low latency recording
- Enable low latency recording path with
  system property
- For 2 buffers and 2048 bytes, reduce
  PLAYBACK_LOW_LATENCY to 21.5 ms

Change-Id: I3c0d54fa473fe89df5a3924de483f16975f4000e
Signed-off-by: Iliyan Malchev <malchev@google.com>

alsa_sound/AudioStreamOutALSA.cpp

diff --git a/alsa_sound/AudioStreamOutALSA.cpp b/alsa_sound/AudioStreamOutALSA.cpp
index bfc5263..894d9f3 100644
--- a/alsa_sound/AudioStreamOutALSA.cpp
+++ b/alsa_sound/AudioStreamOutALSA.cpp
@@ -131,16 +131,19 @@
             if ((use_case == NULL) || (!strcmp(use_case, SND_USE_CASE_VERB_INACTIVE))) {
                 if(!strcmp(mHandle->useCase, SND_USE_CASE_VERB_IP_VOICECALL)){
                      strlcpy(mHandle->useCase, SND_USE_CASE_VERB_IP_VOICECALL,sizeof(mHandle->useCase));
-                 }
-                 else {
-                     strlcpy(mHandle->useCase, SND_USE_CASE_VERB_HIFI, sizeof(mHandle->useCase));
-                 }
+                } else if (mHandle->isDeepbufferOutput){
+                           strlcpy(mHandle->useCase, SND_USE_CASE_VERB_HIFI, sizeof(mHandle->useCase));
+                } else {
+                           strlcpy(mHandle->useCase, SND_USE_CASE_VERB_HIFI_LOWLATENCY_MUSIC, sizeof(mHandle->useCase));
+                }
             } else {
                 if(!strcmp(mHandle->useCase, SND_USE_CASE_MOD_PLAY_VOIP)) {
                     strlcpy(mHandle->useCase, SND_USE_CASE_MOD_PLAY_VOIP,sizeof(mHandle->useCase));
-                 } else {
-                     strlcpy(mHandle->useCase, SND_USE_CASE_MOD_PLAY_MUSIC, sizeof(mHandle->useCase));
-                 }
+                } else if (mHandle->isDeepbufferOutput){
+                           strlcpy(mHandle->useCase, SND_USE_CASE_MOD_PLAY_MUSIC, sizeof(mHandle->useCase));
+                } else {
+                           strlcpy(mHandle->useCase, SND_USE_CASE_MOD_PLAY_LOWLATENCY_MUSIC, sizeof(mHandle->useCase));
+                }
             }
             free(use_case);
             if((!strcmp(mHandle->useCase, SND_USE_CASE_VERB_IP_VOICECALL)) ||
@@ -168,6 +171,7 @@
                   mHandle->module->route(mHandle, mDevices , mParent->mode());
             }
             if (!strcmp(mHandle->useCase, SND_USE_CASE_VERB_HIFI) ||
+                !strcmp(mHandle->useCase, SND_USE_CASE_VERB_HIFI_LOWLATENCY_MUSIC) ||
                 !strcmp(mHandle->useCase, SND_USE_CASE_VERB_IP_VOICECALL)) {
                 snd_use_case_set(mHandle->ucMgr, "_verb", mHandle->useCase);
             } else {