commit 6d7b119a416c9f10288051e562f294365e5d954c
author Andy Hung <hunga@google.com> Sat May 07 22:59:48 2016 -0700
committer Andy Hung <hunga@google.com> Mon May 09 11:42:57 2016 -0700
tree 734bff32a20de4a97c24271b745795db3871cd0f
parent 0b667e2f6f9e871e2fdc89100b8ef4cc623adec2

Improve timestamp jitter fix

Use last valid kernel timestamp on server side, not client side.

Bug: 28465713
Change-Id: I33590d6922980f288355f947bc56279245058429

services/audioflinger/Threads.cpp

diff --git a/services/audioflinger/Threads.cpp b/services/audioflinger/Threads.cpp
index 228426a..bee0447 100644
--- a/services/audioflinger/Threads.cpp
+++ b/services/audioflinger/Threads.cpp
@@ -2899,6 +2899,24 @@
                 // sink will block whie writing.
                 ExtendedTimestamp timestamp; // use private copy to fetch
                 (void) mNormalSink->getTimestamp(timestamp);
+
+                // We keep track of the last valid kernel position in case we are in underrun
+                // and the normal mixer period is the same as the fast mixer period, or there
+                // is some error from the HAL.
+                if (mTimestamp.mTimeNs[ExtendedTimestamp::LOCATION_KERNEL] >= 0) {
+                    mTimestamp.mPosition[ExtendedTimestamp::LOCATION_KERNEL_LASTKERNELOK] =
+                            mTimestamp.mPosition[ExtendedTimestamp::LOCATION_KERNEL];
+                    mTimestamp.mTimeNs[ExtendedTimestamp::LOCATION_KERNEL_LASTKERNELOK] =
+                            mTimestamp.mTimeNs[ExtendedTimestamp::LOCATION_KERNEL];
+
+                    mTimestamp.mPosition[ExtendedTimestamp::LOCATION_SERVER_LASTKERNELOK] =
+                            mTimestamp.mPosition[ExtendedTimestamp::LOCATION_SERVER];
+                    mTimestamp.mTimeNs[ExtendedTimestamp::LOCATION_SERVER_LASTKERNELOK] =
+                            mTimestamp.mTimeNs[ExtendedTimestamp::LOCATION_SERVER];
+                } else {
+                    ALOGV("getTimestamp error - no valid kernel position");
+                }
+
                 // copy over kernel info
                 mTimestamp.mPosition[ExtendedTimestamp::LOCATION_KERNEL] =
                         timestamp.mPosition[ExtendedTimestamp::LOCATION_KERNEL];