void StimulusDisplay::stateSystemCallback(const Datum &data, MWorksTime time) {
unique_lock lock(display_lock);
int newState = data.getInteger();
if ((IDLE == newState) && displayLinksRunning) {
// If another thread is waiting for a display refresh, allow it to complete before stopping
// the display link
while (waitingForRefresh) {
refreshCond.wait(lock);
}
displayLinksRunning = false;
currentOutputTimeUS = -1;
// We need to release the lock before calling CVDisplayLinkStop, because
// StimulusDisplay::displayLinkCallback could be blocked waiting for the lock, and
// CVDisplayLinkStop won't return until displayLinkCallback exits, leading to deadlock.
lock.unlock();
// NOTE: As of OS X 10.11, stopping the display links from a non-main thread causes issues
dispatch_sync(dispatch_get_main_queue(), ^{
for (auto dl : displayLinks) {
if (kCVReturnSuccess != CVDisplayLinkStop(dl)) {
merror(M_DISPLAY_MESSAGE_DOMAIN,
"Unable to stop updates on display %d",
CVDisplayLinkGetCurrentCGDisplay(dl));
}
}
});
mprintf(M_DISPLAY_MESSAGE_DOMAIN, "Display updates stopped");
} else if ((RUNNING == newState) && !displayLinksRunning) {
void StimulusDisplay::stateSystemCallback(const Datum &data, MWorksTime time) {
unique_lock lock(display_lock);
int newState = data.getInteger();
if (IDLE == newState) {
if (CVDisplayLinkIsRunning(displayLink)) {
// If another thread is waiting for a display refresh, allow it to complete before stopping
// the display link
while (waitingForRefresh) {
refreshCond.wait(lock);
}
// We need to release the lock before calling CVDisplayLinkStop, because
// StimulusDisplay::displayLinkCallback could be blocked waiting for the lock, and
// CVDisplayLinkStop won't return until displayLinkCallback exits, leading to deadlock.
lock.unlock();
if (kCVReturnSuccess != CVDisplayLinkStop(displayLink)) {
merror(M_DISPLAY_MESSAGE_DOMAIN, "Unable to stop display updates");
} else {
currentOutputTimeUS = -1;
mprintf(M_DISPLAY_MESSAGE_DOMAIN, "Display updates stopped");
}
}
} else if (RUNNING == newState) {
if (!CVDisplayLinkIsRunning(displayLink)) {
lastFrameTime = 0;
if (kCVReturnSuccess != CVDisplayLinkStart(displayLink)) {
merror(M_DISPLAY_MESSAGE_DOMAIN, "Unable to start display updates");
} else {
// Wait for a refresh to complete, so we know that getCurrentOutputTimeUS() will return a valid time
ensureRefresh(lock);
mprintf(M_DISPLAY_MESSAGE_DOMAIN,
"Display updates started (main = %d, current = %d)",
CGMainDisplayID(),
CVDisplayLinkGetCurrentCGDisplay(displayLink));
}
}
}
}
