Add patch to fix crash when selecting display with no modes (rhbz#1756553)

588.patch

@@ -0,0 +1,63 @@
+From 0d41cfd6b39935940aa573af3a2e0a1492e6aadc Mon Sep 17 00:00:00 2001
+From: Benjamin Berg <bberg@redhat.com>
+Date: Thu, 10 Oct 2019 09:50:30 +0200
+Subject: [PATCH 1/2] display: Add guard for NULL mode in supported scale check
+
+This may prevent crashes in certain error situations.
+---
+ panels/display/cc-display-config-dbus.c | 4 +++-
+ 1 file changed, 3 insertions(+), 1 deletion(-)
+
+diff --git a/panels/display/cc-display-config-dbus.c b/panels/display/cc-display-config-dbus.c
+index 81b2c46f7..cdddbb695 100644
+--- a/panels/display/cc-display-config-dbus.c
++++ b/panels/display/cc-display-config-dbus.c
+@@ -107,8 +107,10 @@ cc_display_mode_dbus_is_supported_scale (CcDisplayMode *pself,
+                                          double scale)
+ {
+   CcDisplayModeDBus *self = CC_DISPLAY_MODE_DBUS (pself);
+-
+   guint i;
++
++  g_return_val_if_fail (pself != NULL, FALSE);
++
+   for (i = 0; i < self->supported_scales->len; i++)
+     if (g_array_index (self->supported_scales, double, i) == scale)
+       return TRUE;
+-- 
+2.22.0
+
+
+From 74687108af9241bd12d95a8391a54103ed2bcc78 Mon Sep 17 00:00:00 2001
+From: Benjamin Berg <bberg@redhat.com>
+Date: Thu, 10 Oct 2019 09:51:55 +0200
+Subject: [PATCH 2/2] display: Use correct mode for supported scale checking
+
+Monitors may not always have a mode. This means we cannot look up the
+mode on the fly, but instead need to have a heuristic to select a mode
+if there is none.
+
+Everything was in place already for this, except that one location was
+still doing a fresh lookup, possibly causing a crash.
+
+Fixes: #675
+---
+ panels/display/cc-display-settings.c | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/panels/display/cc-display-settings.c b/panels/display/cc-display-settings.c
+index fe2643ede..d793fccaa 100644
+--- a/panels/display/cc-display-settings.c
++++ b/panels/display/cc-display-settings.c
+@@ -397,7 +397,7 @@ cc_display_settings_rebuild_ui (CcDisplaySettings *self)
+       GtkWidget *scale_btn;
+ 
+       if (!cc_display_config_is_scaled_mode_valid (self->config,
+-                                                   cc_display_monitor_get_mode (self->selected_output),
++                                                   current_mode,
+                                                    *scale) &&
+           cc_display_monitor_get_scale (self->selected_output) != *scale)
+         continue;
+-- 
+2.22.0
+

gnome-control-center.spec

@@ -10,7 +10,7 @@
 
 Name:           gnome-control-center
 Version:        3.34.1
-Release:        3%{?dist}
+Release:        4%{?dist}
 Summary:        Utilities to configure the GNOME desktop
 
 License:        GPLv2+ and CC-BY-SA
@@ -26,6 +26,10 @@ Patch1:         0001-region-Explicitly-update-LC_-even-when-matching-LANG.patch
 # https://gitlab.gnome.org/GNOME/gnome-control-center/merge_requests/587
 Patch2:         printers-provide-scheme-to-address-parser.patch
 
+# https://gitlab.gnome.org/GNOME/gnome-control-center/merge_requests/588
+# https://bugzilla.redhat.com/show_bug.cgi?id=1756553
+Patch3:         588.patch
+
 BuildRequires:  chrpath
 BuildRequires:  cups-devel
 BuildRequires:  desktop-file-utils
@@ -195,6 +199,9 @@ chrpath --delete $RPM_BUILD_ROOT%{_bindir}/gnome-control-center
 %dir %{_datadir}/gnome/wm-properties
 
 %changelog
+* Thu Oct 10 2019 Adam Williamson <awilliam@redhat.com> - 3.34.1-4
+- Add patch to fix crash when selecting display with no modes (rhbz#1756553)
+
 * Wed Oct 09 2019 Felipe Borges <feborges@redhat.com> - 3.34.1-3
 - Add patch to fix parsing of addresses while adding printers (rhbz#1750394)