From 1e04c474ab59a61faf8d033bf2b8c0fbaf1ce1a1 Mon Sep 17 00:00:00 2001
From: wm4 <wm4@nowhere>
Date: Sun, 17 Aug 2014 15:38:47 +0200
Subject: x11: listen to xrandr events

If the Xrandr configuration changes, re-read it. So if you change
display modes or screen configuration, it will update the framedrop
refresh rate accordingly.

This passes the rootwin to XRRSelectInput(), which may or may not be
allowed. But it works, and the documentation (which is worse than used
toilet paper, great job Xorg) doesn't forbid it, or in fact say anything
about what the window parameter is even used for.
---
 old-configure          |  2 +-
 video/out/x11_common.c | 16 ++++++++++++++++
 video/out/x11_common.h |  2 ++
 wscript                |  2 +-
 4 files changed, 20 insertions(+), 2 deletions(-)

diff --git a/old-configure b/old-configure
index b4b1f7cf2b..b32c9f0598 100755
--- a/old-configure
+++ b/old-configure
@@ -634,7 +634,7 @@ fi
 
 check_pkg_config "Xinerama" $_xinerama XINERAMA 'xinerama'
 
-check_pkg_config "Xrandr" $_xrandr XRANDR 'xrandr'
+check_pkg_config "Xrandr" $_xrandr XRANDR 'xrandr >= 1.2.0'
 
 check_pkg_config "CACA" $_caca CACA 'caca >= 0.99.beta18'
 
diff --git a/video/out/x11_common.c b/video/out/x11_common.c
index f1b69e4f55..6d5485edf2 100644
--- a/video/out/x11_common.c
+++ b/video/out/x11_common.c
@@ -327,6 +327,17 @@ static void xrandr_read(struct vo_x11_state *x11)
 #if HAVE_XRANDR
     x11->num_displays = 0;
 
+    if (x11->xrandr_event < 0) {
+        int event_base, error_base;
+        if (!XRRQueryExtension(x11->display, &event_base, &error_base)) {
+            MP_VERBOSE(x11, "Couldn't init Xrandr.\n");
+            return;
+        }
+        x11->xrandr_event = event_base + RRNotify;
+        XRRSelectInput(x11->display, x11->rootwin, RRScreenChangeNotifyMask |
+                       RRCrtcChangeNotifyMask | RROutputChangeNotifyMask);
+    }
+
     XRRScreenResources *r = XRRGetScreenResources(x11->display, x11->rootwin);
     if (!r) {
         MP_VERBOSE(x11, "Xrandr doesn't work.\n");
@@ -452,6 +463,7 @@ int vo_x11_init(struct vo *vo)
     *x11 = (struct vo_x11_state){
         .log = mp_log_new(x11, vo->log, "x11"),
         .screensaver_enabled = true,
+        .xrandr_event = -1,
     };
     vo->x11 = x11;
 
@@ -932,6 +944,10 @@ int vo_x11_check_events(struct vo *vo)
                 if (x11->ShmCompletionWaitCount > 0)
                     x11->ShmCompletionWaitCount--;
             }
+            if (Event.type == x11->xrandr_event) {
+                xrandr_read(x11);
+                vo_x11_update_geometry(vo);
+            }
             break;
         }
     }
diff --git a/video/out/x11_common.h b/video/out/x11_common.h
index d1ccdd7223..4c11ad1465 100644
--- a/video/out/x11_common.h
+++ b/video/out/x11_common.h
@@ -50,6 +50,8 @@ struct vo_x11_state {
     struct xrandr_display displays[MAX_DISPLAYS];
     int num_displays;
 
+    int xrandr_event;
+
     bool screensaver_enabled;
     bool dpms_touched;
     double screensaver_time_last;
diff --git a/wscript b/wscript
index 13b0e31e51..47cda430d4 100644
--- a/wscript
+++ b/wscript
@@ -569,7 +569,7 @@ video_output_features = [
         'name': '--xrandr',
         'desc': 'Xrandr',
         'deps': [ 'x11' ],
-        'func': check_pkg_config('xrandr'),
+        'func': check_pkg_config('xrandr', '>= 1.2.0'),
     } , {
         'name': '--gl-cocoa',
         'desc': 'OpenGL Cocoa Backend',
-- 
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