diff --git a/src/lib/platform/XWindowsEventQueueBuffer.cpp b/src/lib/platform/XWindowsEventQueueBuffer.cpp index 78f0e5af..8b8c3b59 100644 --- a/src/lib/platform/XWindowsEventQueueBuffer.cpp +++ b/src/lib/platform/XWindowsEventQueueBuffer.cpp @@ -82,6 +82,19 @@ XWindowsEventQueueBuffer::~XWindowsEventQueueBuffer() close(m_pipefd[1]); } +int XWindowsEventQueueBuffer::getPendingCountLocked() +{ + Lock lock(&m_mutex); + // work around a bug in old libx11 which causes the first XPending not to read events under + // certain conditions. The issue happens when libx11 has not yet received replies for all + // flushed events. In that case, internally XPending will not try to process received events + // as the reply for the last event was not found. As a result, XPending will return the number + // of pending events without regard to the events it has just read. + // https://gitlab.freedesktop.org/xorg/lib/libx11/-/merge_requests/1 fixes this on libx11 side. + m_impl->XPending(m_display); + return m_impl->XPending(m_display); +} + void XWindowsEventQueueBuffer::waitForEvent(double dtimeout) { @@ -163,7 +176,7 @@ XWindowsEventQueueBuffer::waitForEvent(double dtimeout) // we want to give the cpu a chance s owe up this to 25ms #define TIMEOUT_DELAY 25 - while (((dtimeout < 0.0) || (remaining > 0)) && QLength(m_display)==0 && retval==0){ + while (((dtimeout < 0.0) || (remaining > 0)) && getPendingCountLocked() == 0 && retval == 0) { #if HAVE_POLL retval = poll(pfds, 2, TIMEOUT_DELAY); //16ms = 60hz, but we make it > to play nicely with the cpu if (pfds[1].revents & POLLIN) { diff --git a/src/lib/platform/XWindowsEventQueueBuffer.h b/src/lib/platform/XWindowsEventQueueBuffer.h index e49b282b..13f6b160 100644 --- a/src/lib/platform/XWindowsEventQueueBuffer.h +++ b/src/lib/platform/XWindowsEventQueueBuffer.h @@ -51,6 +51,8 @@ public: private: void flush(); + int getPendingCountLocked(); + private: typedef std::vector EventList; IXWindowsImpl* m_impl;