From 6c8f0c004f2959bcd92b2850e13737bbf9f72e50 Mon Sep 17 00:00:00 2001
From: Greg Kennedy <kennedy.greg@gmail.com>
Date: Thu, 12 Sep 2019 21:45:38 -0500
Subject: [PATCH] Joystick events send a bogus XWarpPointer event to prevent
 screensaver / dpms launch

---
 unix/unix.cpp | 19 ++++++++++++++++---
 unix/x11.cpp  | 16 +++++++++++++++-
 2 files changed, 31 insertions(+), 4 deletions(-)

diff --git a/unix/unix.cpp b/unix/unix.cpp
index cef2ba94..82118950 100644
--- a/unix/unix.cpp
+++ b/unix/unix.cpp
@@ -166,7 +166,8 @@ static void * S9xProcessSound (void *);
 #endif
 #ifdef JOYSTICK_SUPPORT
 static void InitJoysticks (void);
-static void ReadJoysticks (void);
+static bool8 ReadJoysticks (void);
+void S9xLatchJSEvent();
 #endif
 
 
@@ -1205,8 +1206,10 @@ static void InitJoysticks (void)
 #endif
 }
 
-static void ReadJoysticks (void)
+static bool8 ReadJoysticks (void)
 {
+	// track if ANY joystick event happened this frame
+	int js_latch = FALSE;
 #ifdef JSIOCGVERSION
 	struct js_event	js_ev;
 
@@ -1220,6 +1223,7 @@ static void ReadJoysticks (void)
 			{
 				fprintf(stderr,"Joystick %d reconnected.\n",i);
 				js_unplugged[i] = FALSE;
+				js_latch = TRUE;
 			}
 		}
 
@@ -1233,12 +1237,14 @@ static void ReadJoysticks (void)
 				case JS_EVENT_AXIS:
 					S9xReportAxis(0x8000c000 | (i << 24) | js_ev.number, js_ev.value);
 					S9xReportAxis(0x80008000 | (i << 24) | (js_mod[i] << 16) | js_ev.number, js_ev.value);
+					js_latch = TRUE;
 					break;
 
 				case JS_EVENT_BUTTON:
 				case JS_EVENT_BUTTON | JS_EVENT_INIT:
 					S9xReportButton(0x80004000 | (i << 24) | js_ev.number, js_ev.value);
 					S9xReportButton(0x80000000 | (i << 24) | (js_mod[i] << 16) | js_ev.number, js_ev.value);
+					js_latch = TRUE;
 					break;
 			}
 		}
@@ -1260,9 +1266,12 @@ static void ReadJoysticks (void)
 				S9xReportButton(0x80004000 | (i << 24) | j, 0);
 				S9xReportButton(0x80000000 | (i << 24) | (js_mod[i] << 16) | j, 0);
 			}
+
+			js_latch = TRUE;
 		}
 	}
 #endif
+	return js_latch;
 }
 
 #endif
@@ -1766,7 +1775,11 @@ int main (int argc, char **argv)
 
 	#ifdef JOYSTICK_SUPPORT
 		if (unixSettings.JoystickEnabled && (JoypadSkip++ & 1) == 0)
-			ReadJoysticks();
+		{
+			if (ReadJoysticks() == TRUE) {
+				S9xLatchJSEvent();
+			}
+		}
 	#endif
 
 		S9xProcessEvents(FALSE);
diff --git a/unix/x11.cpp b/unix/x11.cpp
index c732a739..38f3e6bd 100644
--- a/unix/x11.cpp
+++ b/unix/x11.cpp
@@ -100,6 +100,7 @@ struct GUIData
 	bool8			mod1_pressed;
 	bool8			no_repeat;
 	bool8			fullscreen;
+	bool8			js_event_latch;
 	int				x_offset;
 	int				y_offset;
 #ifdef USE_XVIDEO
@@ -1452,7 +1453,7 @@ static void Repaint (bool8 isFrameBoundry)
 	if (GUI.use_shared_memory)
 	{
 		XShmPutImage(GUI.display, GUI.window, GUI.gc, GUI.image->ximage, 0, 0, GUI.x_offset, GUI.y_offset, SNES_WIDTH * 2, SNES_HEIGHT_EXTENDED * 2, False);
-		XSync(GUI.display, False);
+		XSync(GUI.display, False); // Is this double-sync?  See XQueryPointer below...
 	}
 	else
 #endif
@@ -1511,8 +1512,21 @@ static bool8 CheckForPendingXEvents (Display *display)
 #endif
 }
 
+void S9xLatchJSEvent ()
+{
+	// record that a JS event happened and was reported to the engine
+	GUI.js_event_latch = TRUE;
+}
+
 void S9xProcessEvents (bool8 block)
 {
+	// Kick the screensaver if a joystick event occurred
+	if (GUI.js_event_latch == TRUE) {
+		XWarpPointer(GUI.display, None, None, 0, 0, 0, 0, 0, 0);
+		GUI.js_event_latch = FALSE;
+	}
+
+	// Process all other X events
 	while (block || CheckForPendingXEvents(GUI.display))
 	{
 		XEvent	event;