update

README.md

@@ -38,6 +38,7 @@
 - [解決Linux內核升級导致vmmon模块加载失败的问题](./doc/解決Linux內核升級导致vmmon模块加载失败的问题.md) 
 - [如何在ArchLinux上安装自签名SSL证书](./doc/如何在ArchLinux上安装自签名SSL证书.md) 
 - [生成并系统范围内安装自签名证书](./doc/在Linux上应用自签名证书.md) 
+- [解决升级后部分GUI程序如VLC无法启动问题](./doc/解决升级后部分GUI程序如VLC无法启动问题.md)
 - ...[Linux Shell 脚本]()
 
 ## Other

doc/解决升级后部分GUI程序如VLC无法启动问题.md

+# FIX 'X11 CONNECTION BROKE' ISSUE IN QT BASED GUI APPLICATIONS LIKE VLC
+
+![troublesome VLC](https://kowalcj0.github.io/img/2018/007/vlc.png)troublesome VLC
+
+If you ever encountered error like this when starting vlc:
+
+```shell
+$ vlc
+VLC media player 3.0.0-rc5 Vetinari (revision 3.0.0-rc5-0-gf53236af09)
+[0000560cfbe38410] main libvlc: Running vlc with the default interface. Use 'cvlc' to use vlc without interface.
+The X11 connection broke: Maximum allowed requested length exceeded (code 4)
+XIO:  fatal IO error 22 (Invalid argument) on X server ":0"
+      after 447 requests (447 known processed) with 0 events remaining.
+QMutex: destroying locked mutex
+```
+
+Then you can fix it by setting the `QT_AUTO_SCREEN_SCALE_FACTOR` env variable to `0`, i.e.:
+
+```shell
+QT_AUTO_SCREEN_SCALE_FACTOR=0 vlc your_video_file.mkv
+```
+
+You can also modify the `.desktop` file so that this variable is always set, when you start the application via e.g. apps menu: In `/usr/share/applications/vlc.desktop` replace:
+
+```shell
+Exec=/usr/bin/vlc --started-from-file %U
+```
+
+with:
+
+```shell
+Exec=env QT_AUTO_SCREEN_SCALE_FACTOR=0 /usr/bin/vlc --started-from-file %U
+```
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