From 88d4d07745c2867a7c8cdef9ac3cbc80179eb962 Mon Sep 17 00:00:00 2001
From: Francis Lecavalier <flecavalier@sat.qc.ca>
Date: Wed, 4 Dec 2019 11:03:40 -0500
Subject: [PATCH] X11: Fix crash when querying video mode/position of
 disconnected monitor

---
 src/x11_monitor.c | 21 +++++++++++++--------
 1 file changed, 13 insertions(+), 8 deletions(-)

diff --git a/src/x11_monitor.c b/src/x11_monitor.c
index 4d3e1a942..3c1bfc404 100644
--- a/src/x11_monitor.c
+++ b/src/x11_monitor.c
@@ -322,12 +322,14 @@ void _glfwPlatformGetMonitorPos(_GLFWmonitor* monitor, int* xpos, int* ypos)
             XRRGetScreenResourcesCurrent(_glfw.x11.display, _glfw.x11.root);
         XRRCrtcInfo* ci = XRRGetCrtcInfo(_glfw.x11.display, sr, monitor->x11.crtc);
 
-        if (xpos)
-            *xpos = ci->x;
-        if (ypos)
-            *ypos = ci->y;
+        if (ci) {
+            if (xpos)
+                *xpos = ci->x;
+            if (ypos)
+                *ypos = ci->y;
 
-        XRRFreeCrtcInfo(ci);
+            XRRFreeCrtcInfo(ci);
+        }
         XRRFreeScreenResources(sr);
     }
 }
@@ -493,9 +495,12 @@ void _glfwPlatformGetVideoMode(_GLFWmonitor* monitor, GLFWvidmode* mode)
             XRRGetScreenResourcesCurrent(_glfw.x11.display, _glfw.x11.root);
         XRRCrtcInfo* ci = XRRGetCrtcInfo(_glfw.x11.display, sr, monitor->x11.crtc);
 
-        *mode = vidmodeFromModeInfo(getModeInfo(sr, ci->mode), ci);
-
-        XRRFreeCrtcInfo(ci);
+        if (ci) {
+            const XRRModeInfo* mi = getModeInfo(sr, ci->mode);
+            if (mi) // mi can be NULL if the monitor has been disconnected
+                *mode = vidmodeFromModeInfo(mi, ci);
+            XRRFreeCrtcInfo(ci);
+        }
         XRRFreeScreenResources(sr);
     }
     else