Replace "lower power mode" experiment
This replaces the previous low-power mode experiment, which
discarded refresh events, with a new experiment that alters
the refresh period.
(see also I2849e5ea335c0d2509fea1c315392bce7f20451d )
The feature is enabled by specifying a nonzero value for the
"refresh skip count", which indicates the number of periods
to skip. For example, the command:
adb shell service call SurfaceFlinger 1016 i32 1
sets a skip count of '1', yielding a 30Hz refresh rate on a device
with a 60Hz display. Changing the last value to '2' would set the
refresh to 20Hz. '0' returns to the default behavior.
Bug 15523257
Change-Id: I00039c22a55750e74035644c63800e4bee1c774a
diff --git a/services/surfaceflinger/DispSync.cpp b/services/surfaceflinger/DispSync.cpp
index c60834e..12da9a5 100644
--- a/services/surfaceflinger/DispSync.cpp
+++ b/services/surfaceflinger/DispSync.cpp
@@ -53,10 +53,7 @@
public:
DispSyncThread():
- mLowPowerMode(false),
mStop(false),
- mLastVsyncSent(false),
- mLastBufferFull(false),
mPeriod(0),
mPhase(0),
mWakeupLatency(0) {
@@ -140,18 +137,7 @@
}
if (callbackInvocations.size() > 0) {
- if (mLowPowerMode) {
- if (!mLastVsyncSent || !mLastBufferFull) {
- fireCallbackInvocations(callbackInvocations);
- mLastVsyncSent = true;
- } else
- mLastVsyncSent = false;
- } else {
- fireCallbackInvocations(callbackInvocations);
- }
- mLastBufferFull = true;
- } else {
- mLastBufferFull = false;
+ fireCallbackInvocations(callbackInvocations);
}
}
@@ -205,7 +191,6 @@
return !mEventListeners.empty();
}
- bool mLowPowerMode;
private:
struct EventListener {
@@ -278,8 +263,6 @@
}
bool mStop;
- bool mLastVsyncSent;
- bool mLastBufferFull;
nsecs_t mPeriod;
nsecs_t mPhase;
@@ -304,8 +287,10 @@
bool mParity;
};
-DispSync::DispSync() {
- mThread = new DispSyncThread();
+DispSync::DispSync() :
+ mRefreshSkipCount(0),
+ mThread(new DispSyncThread()) {
+
mThread->run("DispSync", PRIORITY_URGENT_DISPLAY + PRIORITY_MORE_FAVORABLE);
reset();
@@ -404,8 +389,11 @@
return mThread->addEventListener(phase, callback);
}
-void DispSync::setLowPowerMode(bool enabled) {
- mThread->mLowPowerMode = enabled;
+void DispSync::setRefreshSkipCount(int count) {
+ Mutex::Autolock lock(mMutex);
+ ALOGD("setRefreshSkipCount(%d)", count);
+ mRefreshSkipCount = count;
+ updateModelLocked();
}
status_t DispSync::removeEventListener(const sp<Callback>& callback) {
@@ -456,6 +444,9 @@
ATRACE_INT64("DispSync:Phase", mPhase);
}
+ // Artificially inflate the period if requested.
+ mPeriod += mPeriod * mRefreshSkipCount;
+
mThread->updateModel(mPeriod, mPhase);
}
}
@@ -465,15 +456,19 @@
return;
}
+ // Need to compare present fences against the un-adjusted refresh period,
+ // since they might arrive between two events.
+ nsecs_t period = mPeriod / (1 + mRefreshSkipCount);
+
int numErrSamples = 0;
nsecs_t sqErrSum = 0;
for (size_t i = 0; i < NUM_PRESENT_SAMPLES; i++) {
nsecs_t sample = mPresentTimes[i];
if (sample > mPhase) {
- nsecs_t sampleErr = (sample - mPhase) % mPeriod;
- if (sampleErr > mPeriod / 2) {
- sampleErr -= mPeriod;
+ nsecs_t sampleErr = (sample - mPhase) % period;
+ if (sampleErr > period / 2) {
+ sampleErr -= period;
}
sqErrSum += sampleErr * sampleErr;
numErrSamples++;
@@ -510,8 +505,8 @@
Mutex::Autolock lock(mMutex);
result.appendFormat("present fences are %s\n",
kIgnorePresentFences ? "ignored" : "used");
- result.appendFormat("mPeriod: %" PRId64 " ns (%.3f fps)\n",
- mPeriod, 1000000000.0 / mPeriod);
+ result.appendFormat("mPeriod: %" PRId64 " ns (%.3f fps; skipCount=%d)\n",
+ mPeriod, 1000000000.0 / mPeriod, mRefreshSkipCount);
result.appendFormat("mPhase: %" PRId64 " ns\n", mPhase);
result.appendFormat("mError: %" PRId64 " ns (sqrt=%.1f)\n",
mError, sqrt(mError));