x11: add support for Xss screensaver disabling

in case xdg-screensaver isn't installed.

Makefile.common

@@ -1305,6 +1305,9 @@ ifeq ($(HAVE_X11), 1)
    ifeq ($(HAVE_XCB),1)
       LIBS += -lX11-xcb
    endif
+   ifeq ($(HAVE_XSCRNSAVER),1)
+      LIBS += -lXss
+   endif
    ifneq ($(HAVE_OPENGLES), 1)
       OBJ += gfx/drivers_context/x_ctx.o
    endif

gfx/common/x11_common.c

@@ -204,6 +204,28 @@ void x11_set_window_attr(Display *dpy, Window win)
    x11_set_window_pid(dpy, win);
 }
 
+#ifdef HAVE_XSCRNSAVER
+#include <X11/extensions/scrnsaver.h>
+static bool xss_screensaver_inhibit(Display *dpy, bool enable)
+{
+    int dummy, min, maj;
+    if (!XScreenSaverQueryExtension(dpy, &dummy, &dummy) ||
+        !XScreenSaverQueryVersion(dpy, &maj, &min) ||
+            maj < 1 || (maj == 1 && min < 1)) {
+            return false;
+        }
+    XScreenSaverSuspend(dpy, enable);
+    XResetScreenSaver(dpy);
+    return true;
+}
+#else
+static bool xss_screensaver_inhibit(Display *dpy, bool enable)
+{
+    (void) dpy;
+    return false;
+}
+#endif
+
 static void xdg_screensaver_inhibit(Window wnd)
 {
    int  ret;
@@ -253,9 +275,11 @@ bool x11_suspend_screensaver(void *data, bool enable)
     if (dbus_suspend_screensaver(enable))
        return true;
 #endif
-    if (enable)
-       if (xdg_screensaver_available)
+    if (!xss_screensaver_inhibit(g_x11_dpy, enable) && enable)
+       if (xdg_screensaver_available) {
           xdg_screensaver_inhibit(wnd);
+          return xdg_screensaver_available;
+       }
     return true;
 }
 

qb/config.libs.sh

@@ -505,6 +505,7 @@ if [ "$HAVE_X11" != 'no' ]; then
    check_val '' XCB -lxcb '' xcb '' '' false
    check_val '' XEXT -lXext '' xext '' '' false
    check_val '' XF86VM -lXxf86vm '' xxf86vm '' '' false
+   check_val '' XSCRNSAVER -lXss '' xscrnsaver '' '' false
 else
    die : 'Notice: X11 not present. Skipping X11 code paths.'
 fi

qb/config.params.sh

@@ -92,6 +92,7 @@ HAVE_OPENGLES3_1=no        # OpenGLES3.1 support
 HAVE_OPENGLES3_2=no        # OpenGLES3.2 support
 HAVE_X11=auto              # everything X11.
 HAVE_XRANDR=auto           # Xrandr support.
+HAVE_XSCRNSAVER=auto       # Xss support.
 HAVE_OMAP=no               # OMAP video support
 HAVE_XINERAMA=auto         # Xinerama support.
 HAVE_KMS=auto              # KMS context support