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-rw-r--r--services/surfaceflinger/EventThread.cpp184
1 files changed, 88 insertions, 96 deletions
diff --git a/services/surfaceflinger/EventThread.cpp b/services/surfaceflinger/EventThread.cpp
index 3833f48..a39b7d8 100644
--- a/services/surfaceflinger/EventThread.cpp
+++ b/services/surfaceflinger/EventThread.cpp
@@ -19,6 +19,8 @@
#include <stdint.h>
#include <sys/types.h>
+#include <cutils/compiler.h>
+
#include <gui/BitTube.h>
#include <gui/IDisplayEventConnection.h>
#include <gui/DisplayEventReceiver.h>
@@ -58,14 +60,6 @@ status_t EventThread::registerDisplayEventConnection(
return NO_ERROR;
}
-status_t EventThread::unregisterDisplayEventConnection(
- const wp<EventThread::Connection>& connection) {
- Mutex::Autolock _l(mLock);
- mDisplayEventConnections.remove(connection);
- mCondition.broadcast();
- return NO_ERROR;
-}
-
void EventThread::removeDisplayEventConnection(
const wp<EventThread::Connection>& connection) {
Mutex::Autolock _l(mLock);
@@ -120,118 +114,115 @@ void EventThread::onVSyncReceived(int, nsecs_t timestamp) {
}
bool EventThread::threadLoop() {
+ DisplayEventReceiver::Event vsync;
+ Vector< sp<EventThread::Connection> > signalConnections;
+ signalConnections = waitForEvent(&vsync);
+
+ // dispatch vsync events to listeners...
+ const size_t count = signalConnections.size();
+ for (size_t i=0 ; i<count ; i++) {
+ const sp<Connection>& conn(signalConnections[i]);
+ // now see if we still need to report this VSYNC event
+ status_t err = conn->postEvent(vsync);
+ if (err == -EAGAIN || err == -EWOULDBLOCK) {
+ // The destination doesn't accept events anymore, it's probably
+ // full. For now, we just drop the events on the floor.
+ // Note that some events cannot be dropped and would have to be
+ // re-sent later. Right-now we don't have the ability to do
+ // this, but it doesn't matter for VSYNC.
+ } else if (err < 0) {
+ // handle any other error on the pipe as fatal. the only
+ // reasonable thing to do is to clean-up this connection.
+ // The most common error we'll get here is -EPIPE.
+ removeDisplayEventConnection(signalConnections[i]);
+ }
+ }
+ return true;
+}
+
+Vector< sp<EventThread::Connection> > EventThread::waitForEvent(
+ DisplayEventReceiver::Event* event)
+{
+ Mutex::Autolock _l(mLock);
- nsecs_t timestamp;
size_t vsyncCount;
- size_t activeEvents;
- DisplayEventReceiver::Event vsync;
- Vector< sp<EventThread::Connection> > activeConnections;
+ nsecs_t timestamp;
+ Vector< sp<EventThread::Connection> > signalConnections;
do {
- Mutex::Autolock _l(mLock);
// latch VSYNC event if any
+ bool waitForVSync = false;
+ vsyncCount = mVSyncCount;
timestamp = mVSyncTimestamp;
mVSyncTimestamp = 0;
- // check if we should be waiting for VSYNC events
- activeEvents = 0;
- bool waitForNextVsync = false;
+ // find out connections waiting for events
size_t count = mDisplayEventConnections.size();
for (size_t i=0 ; i<count ; i++) {
sp<Connection> connection(mDisplayEventConnections[i].promote());
if (connection != NULL) {
- activeConnections.add(connection);
if (connection->count >= 0) {
- // at least one continuous mode or active one-shot event
- waitForNextVsync = true;
- activeEvents++;
- break;
+ // we need vsync events because at least
+ // one connection is waiting for it
+ waitForVSync = true;
+ if (timestamp) {
+ // we consume the event only if it's time
+ // (ie: we received a vsync event)
+ if (connection->count == 0) {
+ // fired this time around
+ connection->count = -1;
+ signalConnections.add(connection);
+ } else if (connection->count == 1 ||
+ (vsyncCount % connection->count) == 0) {
+ // continuous event, and time to report it
+ signalConnections.add(connection);
+ }
+ }
}
+ } else {
+ // we couldn't promote this reference, the connection has
+ // died, so clean-up!
+ mDisplayEventConnections.removeAt(i);
+ --i; --count;
}
}
- if (timestamp) {
- if (!waitForNextVsync) {
- // we received a VSYNC but we have no clients
- // don't report it, and disable VSYNC events
- disableVSyncLocked();
- } else {
- // report VSYNC event
- break;
- }
- } else {
- // never disable VSYNC events immediately, instead
- // we'll wait to receive the event and we'll
- // reevaluate whether we need to dispatch it and/or
- // disable VSYNC events then.
- if (waitForNextVsync) {
- // enable
- enableVSyncLocked();
- }
+ // Here we figure out if we need to enable or disable vsyncs
+ if (timestamp && !waitForVSync) {
+ // we received a VSYNC but we have no clients
+ // don't report it, and disable VSYNC events
+ disableVSyncLocked();
+ } else if (!timestamp && waitForVSync) {
+ enableVSyncLocked();
}
- // wait for something to happen
- if (mUseSoftwareVSync && waitForNextVsync) {
- // h/w vsync cannot be used (screen is off), so we use
- // a timeout instead. it doesn't matter how imprecise this
- // is, we just need to make sure to serve the clients
- if (mCondition.waitRelative(mLock, ms2ns(16)) == TIMED_OUT) {
- mVSyncTimestamp = systemTime(SYSTEM_TIME_MONOTONIC);
- mVSyncCount++;
+ // note: !timestamp implies signalConnections.isEmpty()
+ if (!timestamp) {
+ // wait for something to happen
+ if (CC_UNLIKELY(mUseSoftwareVSync && waitForVSync)) {
+ // h/w vsync cannot be used (screen is off), so we use
+ // a timeout instead. it doesn't matter how imprecise this
+ // is, we just need to make sure to serve the clients
+ if (mCondition.waitRelative(mLock, ms2ns(16)) == TIMED_OUT) {
+ mVSyncTimestamp = systemTime(SYSTEM_TIME_MONOTONIC);
+ mVSyncCount++;
+ }
+ } else {
+ // This is where we spend most of our time, waiting
+ // for a vsync events and registered clients
+ mCondition.wait(mLock);
}
- } else {
- mCondition.wait(mLock);
}
- vsyncCount = mVSyncCount;
- } while (!activeConnections.size());
+ } while (signalConnections.isEmpty());
- if (!activeEvents) {
- // no events to return. start over.
- // (here we make sure to exit the scope of this function
- // so that we release our Connection references)
- return true;
- }
+ // here we're guaranteed to have a timestamp and some connections to signal
// dispatch vsync events to listeners...
- vsync.header.type = DisplayEventReceiver::DISPLAY_EVENT_VSYNC;
- vsync.header.timestamp = timestamp;
- vsync.vsync.count = vsyncCount;
+ event->header.type = DisplayEventReceiver::DISPLAY_EVENT_VSYNC;
+ event->header.timestamp = timestamp;
+ event->vsync.count = vsyncCount;
- const size_t count = activeConnections.size();
- for (size_t i=0 ; i<count ; i++) {
- const sp<Connection>& conn(activeConnections[i]);
- // now see if we still need to report this VSYNC event
- const int32_t vcount = conn->count;
- if (vcount >= 0) {
- bool reportVsync = false;
- if (vcount == 0) {
- // fired this time around
- conn->count = -1;
- reportVsync = true;
- } else if (vcount == 1 || (vsyncCount % vcount) == 0) {
- // continuous event, and time to report it
- reportVsync = true;
- }
-
- if (reportVsync) {
- status_t err = conn->postEvent(vsync);
- if (err == -EAGAIN || err == -EWOULDBLOCK) {
- // The destination doesn't accept events anymore, it's probably
- // full. For now, we just drop the events on the floor.
- // Note that some events cannot be dropped and would have to be
- // re-sent later. Right-now we don't have the ability to do
- // this, but it doesn't matter for VSYNC.
- } else if (err < 0) {
- // handle any other error on the pipe as fatal. the only
- // reasonable thing to do is to clean-up this connection.
- // The most common error we'll get here is -EPIPE.
- removeDisplayEventConnection(activeConnections[i]);
- }
- }
- }
- }
-
- return true;
+ return signalConnections;
}
void EventThread::enableVSyncLocked() {
@@ -279,7 +270,8 @@ EventThread::Connection::Connection(
}
EventThread::Connection::~Connection() {
- mEventThread->unregisterDisplayEventConnection(this);
+ // do nothing here -- clean-up will happen automatically
+ // when the main thread wakes up
}
void EventThread::Connection::onFirstRef() {
generated by cgit v1.1 at 2025-08-17 11:23:40 +0000