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/AudioStreamInALSA.cpp

diff --git a/alsa_sound/AudioStreamInALSA.cpp b/alsa_sound/AudioStreamInALSA.cpp
index bf16915..e63d606 100644
--- a/alsa_sound/AudioStreamInALSA.cpp
+++ b/alsa_sound/AudioStreamInALSA.cpp
@@ -178,8 +178,14 @@
 #endif
             } 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_CAPTURE_MUSIC, sizeof(mHandle->useCase));
+            } else {
+                    char value[128];
+                    property_get("persist.audio.lowlatency.rec",value,"0");
+                    if (!strcmp("true", value)) {
+                        strlcpy(mHandle->useCase, SND_USE_CASE_MOD_CAPTURE_LOWLATENCY_MUSIC, sizeof(mHandle->useCase));
+                    } else {
+                        strlcpy(mHandle->useCase, SND_USE_CASE_MOD_CAPTURE_MUSIC, sizeof(mHandle->useCase));
+                    }
             }
         } else {
             if ((mHandle->devices == AudioSystem::DEVICE_IN_VOICE_CALL) &&
@@ -222,7 +228,13 @@
             } else 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_REC, sizeof(mHandle->useCase));
+                    char value[128];
+                    property_get("persist.audio.lowlatency.rec",value,"0");
+                    if (!strcmp("true", value)) {
+                        strlcpy(mHandle->useCase, SND_USE_CASE_VERB_HIFI_LOWLATENCY_REC, sizeof(mHandle->useCase));
+                    } else {
+                        strlcpy(mHandle->useCase, SND_USE_CASE_VERB_HIFI_REC, sizeof(mHandle->useCase));
+                    }
             }
         }
         free(use_case);
@@ -250,6 +262,7 @@
             }
         }
         if (!strcmp(mHandle->useCase, SND_USE_CASE_VERB_HIFI_REC) ||
+            !strcmp(mHandle->useCase, SND_USE_CASE_VERB_HIFI_LOWLATENCY_REC) ||
             !strcmp(mHandle->useCase, SND_USE_CASE_VERB_FM_REC) ||
             !strcmp(mHandle->useCase, SND_USE_CASE_VERB_IP_VOICECALL) ||
             !strcmp(mHandle->useCase, SND_USE_CASE_VERB_FM_A2DP_REC) ||