我有一台 Sager NP8268，并安装了 Xubuntu 14.04。
我已经通过 HDMI 使用外置华硕 PB278Q 显示器约 3 周了。如今，xfce4-display-settings 已无法检测到该显示器。
想弄清楚如何使用自动检测使其再次工作；我不想安装 PPA，或者手动维护 Xorg.conf。
一些信息：
~$ xrandr
Screen 0: minimum 320 x 200, current 1920 x 1080, maximum 32767 x 32767
eDP1 connected 1920x1080+0+0 (normal left inverted right x axis y axis) 344mm x 194mm
1920x1080 60.0*+ 59.9 40.0
1680x1050 60.0 59.9
1600x1024 60.2
1400x1050 60.0
1280x1024 60.0
1440x900 59.9
1280x960 60.0
1360x768 59.8 60.0
1152x864 60.0
1024x768 60.0
800x600 60.3 56.2
640x480 59.9
VGA1 disconnected (normal left inverted right x axis y axis)
DP1 disconnected (normal left inverted right x axis y axis)
HDMI1 disconnected (normal left inverted right x axis y axis)
DP2 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)
~$ lspci | grep VGA
00:02.0 VGA compatible controller: Intel Corporation 4th Gen Core Processor Integrated Graphics Controller (rev 06)
01:00.0 VGA compatible controller: NVIDIA Corporation GK104M [GeForce GTX 860M] (rev a1)
~$ lshw -C video
*-display
description: VGA compatible controller
product: GK104M [GeForce GTX 860M]
vendor: NVIDIA Corporation
physical id: 0
bus info: pci@0000:01:00.0
version: a1
width: 64 bits
clock: 33MHz
capabilities: pm msi pciexpress vga_controller bus_master cap_list rom
configuration: driver=nouveau latency=0
resources: irq:51 memory:f6000000-f6ffffff memory:e0000000-efffffff memory:f0000000-f1ffffff ioport:e000(size=128) memory:f7000000-f707ffff
*-display
description: VGA compatible controller
product: 4th Gen Core Processor Integrated Graphics Controller
vendor: Intel Corporation
physical id: 2
bus info: pci@0000:00:02.0
version: 06
width: 64 bits
clock: 33MHz
capabilities: msi pm vga_controller bus_master cap_list rom
configuration: driver=i915 latency=0
resources: irq:52 memory:f7400000-f77fffff memory:d0000000-dfffffff ioport:f000(size=64)
/var/log/Xorg.0.log——http://pastebin.com/Wfansf5V