core: wait for dmabuf readiness (#9806)

* add doOnReadable to event loop manager

* move syncTimeline addWaiter to doOnReadable

* wait on dmabuf buffers to be readable

* don't over synchronize in scanout, also give present feedback on same buffer commit

1 files changed, 2 insertions, 70 deletions

diff --git a/src/helpers/sync/SyncTimeline.cpp b/src/helpers/sync/SyncTimeline.cpp
index 9f5f5a8a..edb2b190 100644
--- a/src/helpers/sync/SyncTimeline.cpp
+++ b/src/helpers/sync/SyncTimeline.cpp
@@ -34,13 +34,6 @@ SP<CSyncTimeline> CSyncTimeline::create(int drmFD_, CFileDescriptor&& drmSyncobj
 }
 
 CSyncTimeline::~CSyncTimeline() {
-    for (auto& w : waiters) {
-        if (w->source) {
-            wl_event_source_remove(w->source);
-            w->source = nullptr;
-        }
-    }
-
     if (handle == 0)
         return;
 
@@ -64,34 +57,8 @@ std::optional<bool> CSyncTimeline::check(uint64_t point, uint32_t flags) {
     return ret == 0;
 }
 
-static int handleWaiterFD(int fd, uint32_t mask, void* data) {
-    auto waiter = (CSyncTimeline::SWaiter*)data;
-
-    if (mask & (WL_EVENT_HANGUP | WL_EVENT_ERROR)) {
-        Debug::log(ERR, "handleWaiterFD: eventfd error");
-        return 0;
-    }
-
-    if (mask & WL_EVENT_READABLE) {
-        uint64_t value = 0;
-        if (read(fd, &value, sizeof(value)) <= 0)
-            Debug::log(ERR, "handleWaiterFD: failed to read from eventfd");
-    }
-
-    wl_event_source_remove(waiter->source);
-    waiter->source = nullptr;
-
-    if (waiter->fn)
-        waiter->fn();
-
-    if (waiter->timeline)
-        waiter->timeline->removeWaiter(waiter);
-
-    return 0;
-}
-
 bool CSyncTimeline::addWaiter(const std::function<void()>& waiter, uint64_t point, uint32_t flags) {
-    CFileDescriptor eventFd = CFileDescriptor{eventfd(0, EFD_CLOEXEC)};
+    auto eventFd = CFileDescriptor(eventfd(0, EFD_CLOEXEC));
 
     if (!eventFd.isValid()) {
         Debug::log(ERR, "CSyncTimeline::addWaiter: failed to acquire an eventfd");
@@ -103,46 +70,11 @@ bool CSyncTimeline::addWaiter(const std::function<void()>& waiter, uint64_t poin
         return false;
     }
 
-    if (eventFd.isReadable()) {
-        waiter();
-        return true;
-    }
-
-    auto w      = makeShared<SWaiter>();
-    w->fn       = waiter;
-    w->timeline = self;
-    w->eventFd  = std::move(eventFd);
-
-    w->source = wl_event_loop_add_fd(g_pEventLoopManager->m_sWayland.loop, w->eventFd.get(), WL_EVENT_READABLE, ::handleWaiterFD, w.get());
-    if (!w->source) {
-        Debug::log(ERR, "CSyncTimeline::addWaiter: wl_event_loop_add_fd failed");
-        return false;
-    }
-
-    waiters.emplace_back(w);
+    g_pEventLoopManager->doOnReadable(std::move(eventFd), waiter);
 
     return true;
 }
 
-void CSyncTimeline::removeWaiter(SWaiter* w) {
-    if (w->source) {
-        wl_event_source_remove(w->source);
-        w->source = nullptr;
-    }
-    std::erase_if(waiters, [w](const auto& e) { return e.get() == w; });
-}
-
-void CSyncTimeline::removeAllWaiters() {
-    for (auto& w : waiters) {
-        if (w->source) {
-            wl_event_source_remove(w->source);
-            w->source = nullptr;
-        }
-    }
-
-    waiters.clear();
-}
-
 CFileDescriptor CSyncTimeline::exportAsSyncFileFD(uint64_t src) {
     int      sync = -1;