Added support for DPMS in X11 screen saver. DPMS is the extension

that allows you to power down the display.  Previously, synergy
would not power on the display if DPMS was enabled and activated
and xscreensaver was not running.  It also wouldn't disable DPMS
so the display would power down normally on a synergy client if
there was no input activity.

configure.in

@@ -57,8 +57,8 @@ AC_PATH_XTRA
 save_CPPFLAGS="$CPPFLAGS"
 CPPFLAGS="$X_CFLAGS $CPPFLAGS"
 AC_CHECK_HEADERS([X11/extensions/XTest.h])
-
 AC_CHECK_LIB(Xinerama, XineramaQueryExtension, AC_CHECK_HEADERS([X11/extensions/Xinerama.h]) [X_LIBS="$X_LIBS -lXinerama"], , [$X_LIBS -lXext -lX11 $X_EXTRA_LIBS])
+AC_CHECK_LIB(Xext, DPMSQueryExtension, AC_CHECK_HEADERS([X11/extensions/dpms.h]) [X_LIBS="$X_LIBS -lXext"], , [$X_LIBS -lX11 $X_EXTRA_LIBS])
 CPPFLAGS="$save_CPPFLAGS"
 
 dnl checks for types

lib/platform/CXWindowsScreenSaver.cpp

@@ -25,6 +25,11 @@
 #else
 #	error The XTest extension is required to build synergy
 #endif
+#if defined(HAVE_X11_EXTENSIONS_DPMS_H)
+extern "C" {
+#	include <X11/extensions/dpms.h>
+}
+#endif
 
 //
 // CXWindowsScreenSaver
@@ -37,6 +42,7 @@ CXWindowsScreenSaver::CXWindowsScreenSaver(
 	m_eventTarget(eventTarget),
 	m_xscreensaver(None),
 	m_xscreensaverActive(false),
+	m_dpms(false),
 	m_disabled(false),
 	m_suppressDisable(false),
 	m_disableTimer(NULL)
@@ -51,6 +57,18 @@ CXWindowsScreenSaver::CXWindowsScreenSaver(
 	m_atomScreenSaverDeactivate = XInternAtom(m_display,
 										"DEACTIVATE", False);
 
+	// check for DPMS extension.  this is an alternative screen saver
+	// that powers down the display.
+#if defined(HAVE_X11_EXTENSIONS_DPMS_H)
+	int eventBase, errorBase;
+	if (DPMSQueryExtension(m_display, &eventBase, &errorBase)) {
+		if (DPMSCapable(m_display)) {
+			// we have DPMS
+			m_dpms  = true;
+		}
+	}
+#endif
+
 	// watch top-level windows for changes
 	{
 		bool error = false;
@@ -66,15 +84,18 @@ CXWindowsScreenSaver::CXWindowsScreenSaver(
 		}
 	}
 
+	// get the built-in settings
+	XGetScreenSaver(m_display, &m_timeout, &m_interval,
+								&m_preferBlanking, &m_allowExposures);
+
+	// get the DPMS settings
+	m_dpmsEnabled = isDPMSEnabled();
+
 	// get the xscreensaver window, if any
 	if (!findXScreenSaver()) {
 		setXScreenSaver(None);
 	}
 
-	// get the built-in settings
-	XGetScreenSaver(m_display, &m_timeout, &m_interval,
-								&m_preferBlanking, &m_allowExposures);
-
 	// install disable timer event handler
 	EVENTQUEUE->adoptHandler(CEvent::kTimer, this,
 							new TMethodEventJob<CXWindowsScreenSaver>(this,
@@ -90,6 +111,7 @@ CXWindowsScreenSaver::~CXWindowsScreenSaver()
 	EVENTQUEUE->removeHandler(CEvent::kTimer, this);
 
 	if (m_display != NULL) {
+		enableDPMS(m_dpmsEnabled);
 		XSetScreenSaver(m_display, m_timeout, m_interval,
 								m_preferBlanking, m_allowExposures);
 		clearWatchForXScreenSaver();
@@ -176,6 +198,9 @@ CXWindowsScreenSaver::enable()
 	// for built-in X screen saver
 	XSetScreenSaver(m_display, m_timeout, m_interval,
 								m_preferBlanking, m_allowExposures);
+
+	// for DPMS
+	enableDPMS(m_dpmsEnabled);
 }
 
 void
@@ -190,6 +215,11 @@ CXWindowsScreenSaver::disable()
 								&m_preferBlanking, &m_allowExposures);
 	XSetScreenSaver(m_display, 0, m_interval,
 								m_preferBlanking, m_allowExposures);
+
+	// for DPMS
+	m_dpmsEnabled = isDPMSEnabled();
+	enableDPMS(false);
+
 	// FIXME -- now deactivate?
 }
 
@@ -200,6 +230,9 @@ CXWindowsScreenSaver::activate()
 	m_suppressDisable = true;
 	updateDisableTimer();
 
+	// enable DPMS if it was enabled
+	enableDPMS(m_dpmsEnabled);
+
 	// try xscreensaver
 	findXScreenSaver();
 	if (m_xscreensaver != None) {
@@ -207,8 +240,13 @@ CXWindowsScreenSaver::activate()
 		return;
 	}
 
-	// use built-in X screen saver
+	// try built-in X screen saver
+	if (m_timeout != 0) {
 		XForceScreenSaver(m_display, ScreenSaverActive);
+	}
+
+	// try DPMS
+	activateDPMS(true);
 }
 
 void
@@ -218,6 +256,14 @@ CXWindowsScreenSaver::deactivate()
 	m_suppressDisable = false;
 	updateDisableTimer();
 
+	// try DPMS
+	activateDPMS(false);
+
+	// disable DPMS if screen saver is disabled
+	if (m_disabled) {
+		enableDPMS(false);
+	}
+
 	// try xscreensaver
 	findXScreenSaver();
 	if (m_xscreensaver != None) {
@@ -237,6 +283,11 @@ CXWindowsScreenSaver::isActive() const
 		return m_xscreensaverActive;
 	}
 
+	// check DPMS
+	if (isDPMSActivated()) {
+		return true;
+	}
+
 	// can't check built-in X screen saver activity
 	return false;
 }
@@ -282,6 +333,9 @@ CXWindowsScreenSaver::setXScreenSaver(Window window)
 		XWindowAttributes attr;
 		XGetWindowAttributes(m_display, m_xscreensaver, &attr);
 		setXScreenSaverActive(!error && attr.map_state != IsUnmapped);
+
+		// save current DPMS state;  xscreensaver may have changed it.
+		m_dpmsEnabled = isDPMSEnabled();
 	}
 	else {
 		// screen saver can't be active if it doesn't exist
@@ -450,3 +504,66 @@ CXWindowsScreenSaver::handleDisableTimer(const CEvent&, void*)
 		XSendEvent(m_display, m_xscreensaver, False, 0, &event);
 	}
 }
+
+void
+CXWindowsScreenSaver::activateDPMS(bool activate)
+{
+#if defined(HAVE_X11_EXTENSIONS_DPMS_H)
+	if (m_dpms) {
+		// DPMSForceLevel will generate a BadMatch if DPMS is disabled
+		CXWindowsUtil::CErrorLock lock(m_display);
+		DPMSForceLevel(m_display, activate ? DPMSModeStandby : DPMSModeOn);
+	}
+#endif
+}
+
+void
+CXWindowsScreenSaver::enableDPMS(bool enable)
+{
+#if defined(HAVE_X11_EXTENSIONS_DPMS_H)
+	if (m_dpms) {
+		if (enable) {
+			DPMSEnable(m_display);
+		}
+		else {
+			DPMSDisable(m_display);
+		}
+	}
+#endif
+}
+
+bool
+CXWindowsScreenSaver::isDPMSEnabled() const
+{
+#if defined(HAVE_X11_EXTENSIONS_DPMS_H)
+	if (m_dpms) {
+		CARD16 level;
+		BOOL state;
+		DPMSInfo(m_display, &level, &state);
+		return (state != False);
+	}
+	else {
+		return false;
+	}
+#else
+	return false;
+#endif
+}
+
+bool
+CXWindowsScreenSaver::isDPMSActivated() const
+{
+#if defined(HAVE_X11_EXTENSIONS_DPMS_H)
+	if (m_dpms) {
+		CARD16 level;
+		BOOL state;
+		DPMSInfo(m_display, &level, &state);
+		return (level != DPMSModeOn);
+	}
+	else {
+		return false;
+	}
+#else
+	return false;
+#endif
+}

lib/platform/CXWindowsScreenSaver.h

@@ -92,6 +92,18 @@ private:
 	// called periodically to prevent the screen saver from starting
 	void				handleDisableTimer(const CEvent&, void*);
 
+	// force DPMS to activate or deactivate
+	void				activateDPMS(bool activate);
+
+	// enable/disable DPMS screen saver
+	void				enableDPMS(bool);
+
+	// check if DPMS is enabled
+	bool				isDPMSEnabled() const;
+
+	// check if DPMS is activate
+	bool				isDPMSActivated() const;
+
 private:
 	typedef std::map<Window, long> CWatchList;
 
@@ -128,6 +140,10 @@ private:
 	int					m_preferBlanking;
 	int					m_allowExposures;
 
+	// DPMS screen saver settings
+	bool				m_dpms;
+	bool				m_dpmsEnabled;
+
 	// true iff the client wants the screen saver suppressed
 	bool				m_disabled;