我不久前在我的笔记本电脑上安装了 arch linux，一切正常。我自两周左右以来一直面临的问题（最肯定与更新有关）在附加外部显示器登录时发生（登录[[ -z $DISPLAY && $XDG_VTNR -eq 1 ]] && exec startx通过运行.zshrc）：.xinitrc运行randrctl auto（这只是 的包装器xrandr）以检测连接的显示器和根据需要配置它们。这会出现一个错误提示，表明所需的模式不适用于显示器：
ERROR /usr/bin/xrandr: cannot find mode 1680x1050
WM（顺便说一下 i3）启动后立即运行 xrandr 显示以下输出：
date; xrandr
Thu Nov 5 10:15:03 CET 2015
Screen 0: minimum 8 x 8, current 1600 x 900, maximum 32767 x 32767
eDP1 connected 1600x900+0+0 (normal left inverted right x axis y axis) 310mm x 174mm
1600x900 60.05*+
1368x768 60.00
1280x720 60.00
...
720x405 60.00
640x360 60.00
DP1 disconnected (normal left inverted right x axis y axis)
DP2 disconnected (normal left inverted right x axis y axis)
DP2-1 connected 1440x900+0+0 (normal left inverted right x axis y axis) 433mm x 271mm
1440x900 59.90*+
DP2-2 connected 1440x900+0+0 (normal left inverted right x axis y axis) 433mm x 271mm
1440x900 59.90*+
DP2-3 disconnected (normal left inverted right x axis y axis)
HDMI1 disconnected (normal left inverted right x axis y axis)
HDMI2 disconnected (normal left inverted right x axis y axis)
VIRTUAL1 disconnected (normal left inverted right x axis y axis)
这解释了错误，因为 DP2-1 和 DP2-2 可用的模式不是我想要应用的模式。
大约 15 秒后，输出发生变化：
date; xrandr
Thu Nov 5 10:15:16 CET 2015
Screen 0: minimum 8 x 8, current 1600 x 900, maximum 32767 x 32767
eDP1 connected 1600x900+0+0 (normal left inverted right x axis y axis) 310mm x 174mm
1600x900 60.05*+ 40.04
1368x768 60.00
1280x720 60.00
...
720x405 60.00
640x360 60.00
DP1 disconnected (normal left inverted right x axis y axis)
DP2 disconnected (normal left inverted right x axis y axis)
DP2-1 connected 1440x900+0+0 (normal left inverted right x axis y axis) 433mm x 271mm
1680x1050 59.95 +
1280x1024 75.02 60.02
1440x900 59.90*
1280x800 59.91
1152x864 75.00
1280x720 60.00
1024x768 75.08 70.07 60.00
832x624 74.55
800x600 72.19 75.00 60.32 56.25
640x480 75.00 72.81 66.67 60.00
720x400 70.08
DP2-2 connected 1440x900+0+0 (normal left inverted right x axis y axis) 433mm x 271mm
1680x1050 59.95 +
1280x1024 75.02 60.02
1440x900 59.90*
1280x800 59.91
1152x864 75.00
1280x720 60.00
1024x768 75.08 70.07 60.00
832x624 74.55
800x600 72.19 75.00 60.32 56.25
640x480 75.00 72.81 66.67 60.00
720x400 70.08
DP2-3 disconnected (normal left inverted right x axis y axis)
HDMI1 disconnected (normal left inverted right x axis y axis)
HDMI2 disconnected (normal left inverted right x axis y axis)
VIRTUAL1 disconnected (normal left inverted right x axis y axis)
现在正如预期的那样。为什么需要这么长时间？如何解决这个问题？
一些附加信息：
X.Org X Server 1.17.1
X.Org ANSI C Emulation: 0.4
X.Org Video Driver: 19.0
X.Org XInput driver : 21.0
X.Org Server Extension : 9.0
Kernel: Linux 1040 4.2.5-1-ARCH #1 SMP PREEMPT Tue Oct 27 08:13:28 CET 2015 x86_64 GNU/Linux