commit 11c9fb1f90cc786485a53aeb1d31ec1ad1dbf840
author Jon Eklund <jeklund@motorola.com> Mon Jun 23 14:47:03 2014 -0500
committer Eric Laurent <elaurent@google.com> Wed Sep 10 15:53:59 2014 -0700
tree fbd0fb098133f66a3ce0e51947d8964bc9699104
parent 4bcbb07be57947ea1421519094f73577b1e263e6

AudioPolicyManager: Use "safe" speaker for notifications if available

On particularly loud devices, unexpected audio bursts can be harmful.
For longer audio events, the conventional mitigation strategy is to
somehow soft-start (ramp) the loudspeaker volume, but this strategy
can severely impact the audibility of short audio events.

Use of the "safe" speaker path hints to AudioHAL to immediately output
at best allowable level for transient audio events.

SPEAKER_SAFE is aliased to SPEAKER for purposes of volume control.

Bug: 17319721
Change-Id: I75187c23f3d1f18e9f638c5d14e7b0bf805a67bc

services/audiopolicy/AudioPolicyManager.cpp

diff --git a/services/audiopolicy/AudioPolicyManager.cpp b/services/audiopolicy/AudioPolicyManager.cpp
index 6adcde4..22c4e04 100644
--- a/services/audiopolicy/AudioPolicyManager.cpp
+++ b/services/audiopolicy/AudioPolicyManager.cpp
@@ -64,6 +64,7 @@
 const StringToEnum sDeviceNameToEnumTable[] = {
     STRING_TO_ENUM(AUDIO_DEVICE_OUT_EARPIECE),
     STRING_TO_ENUM(AUDIO_DEVICE_OUT_SPEAKER),
+    STRING_TO_ENUM(AUDIO_DEVICE_OUT_SPEAKER_SAFE),
     STRING_TO_ENUM(AUDIO_DEVICE_OUT_WIRED_HEADSET),
     STRING_TO_ENUM(AUDIO_DEVICE_OUT_WIRED_HEADPHONE),
     STRING_TO_ENUM(AUDIO_DEVICE_OUT_BLUETOOTH_SCO),
@@ -3824,6 +3825,14 @@
             break;
         }
     }
+
+    /*Filter SPEAKER_SAFE out of results, as AudioService doesn't know about it
+      and doesn't really need to.*/
+    if (devices & AUDIO_DEVICE_OUT_SPEAKER_SAFE) {
+        devices |= AUDIO_DEVICE_OUT_SPEAKER;
+        devices &= ~AUDIO_DEVICE_OUT_SPEAKER_SAFE;
+    }
+
     return devices;
 }
 
@@ -3926,12 +3935,20 @@
             //   the isStreamActive() method only informs about the activity of a stream, not
             //   if it's for local playback. Note also that we use the same delay between both tests
             device = getDeviceForStrategy(STRATEGY_SONIFICATION, false /*fromCache*/);
+            //user "safe" speaker if available instead of normal speaker to avoid triggering
+            //other acoustic safety mechanisms for notification
+            if (device == AUDIO_DEVICE_OUT_SPEAKER && (availableOutputDeviceTypes & AUDIO_DEVICE_OUT_SPEAKER_SAFE))
+                device = AUDIO_DEVICE_OUT_SPEAKER_SAFE;
         } else if (isStreamActive(AUDIO_STREAM_MUSIC, SONIFICATION_RESPECTFUL_AFTER_MUSIC_DELAY)) {
             // while media is playing (or has recently played), use the same device
             device = getDeviceForStrategy(STRATEGY_MEDIA, false /*fromCache*/);
         } else {
             // when media is not playing anymore, fall back on the sonification behavior
             device = getDeviceForStrategy(STRATEGY_SONIFICATION, false /*fromCache*/);
+            //user "safe" speaker if available instead of normal speaker to avoid triggering
+            //other acoustic safety mechanisms for notification
+            if (device == AUDIO_DEVICE_OUT_SPEAKER && (availableOutputDeviceTypes & AUDIO_DEVICE_OUT_SPEAKER_SAFE))
+                device = AUDIO_DEVICE_OUT_SPEAKER_SAFE;
         }
 
         break;
@@ -4668,6 +4685,10 @@
         }
     }
 
+    /*SPEAKER_SAFE is an alias of SPEAKER for purposes of volume control*/
+    if (device == AUDIO_DEVICE_OUT_SPEAKER_SAFE)
+        device = AUDIO_DEVICE_OUT_SPEAKER;
+
     ALOGW_IF(popcount(device) != 1,
             "getDeviceForVolume() invalid device combination: %08x",
             device);