CentOS 6.6 在Atom 处理器上 GDM登录界面不显示的问题

在一块 Atom 处理器的主板上安装CentOS 6.6 桌面之后，启动之后不显示登录界面。经过网上搜索，发现确实有人遇到同样的问题。问题好像出在Xorg的自动检测显示模式上了。解决办法是，写一个Xorg的config文件，手动配置显示参数。配置文件可以命名为 10-monitor.conf (可随意命名)，复制到 /etc/X11/xorg.conf.d/ 目录下。

配置文件的内容大致如下：

Section "Monitor"
  Identifier "Monitor0"
EndSection

Section "Device"
  Identifier "Device0"
  Driver "intel"         #Choose the driver used for this monitor
EndSection

Section "Screen"
  Identifier "Screen0"   #Collapse Monitor and Device section to Screen section
  Device "Device0"
  Monitor "Monitor0"
  DefaultDepth 24        #depth (16|24)
  SubSection "Display"
       Depth 24
       Modes "1280x1024" "1024x768" "800x600" "640x480"  #resolution
  EndSubSection
EndSection

参考了下面的文章 () ：

[CentOS] SOLUTION: Atom Processor D4xx/D5xx/N4xx/N5xx Integrated Graphics Controller - GDM login doesn't show up

This problem is so damn weird and frustrating that I thought it would be worthwhile to post this solution for anyone who may run into this situation in the future, since I was unable to find any mention of this after much searching, and no error messages appear in any logfiles that I could find either.
This applies to a machine with a Atom Processor D4xx/D5xx/N4xx/N5xx Integrated Graphics Controller (according to what lshw tells me).

PROBLEMS FOUND:

Live CD:
When booting off a a Live CD, the computer boots off of the CD and then loads to the point where the GDM login should show up (and then say "automatic login"), but it stalls at that point and nothing further happens.  The blue gdm background screen appears but nothing more.

Net Install CD:
When installing from a netinstall CD, the entire installation works perfectly (in graphical mode).  After the installation is completed you reboot the machine and the usual firstboot stuff (set timezone, create username, etc) comes up and runs as usual.  After finishing the firstboot stuff, you reboot and the machine loads to the GDM background screen.  The "enter password" box never appears on the screen.

If you log in to text mode, then type startx, the gnome desktop loads to the point that the blue background screen shows up, and that's it. Nothing further happens until you Ctrl-Alt-Backspace and kill the Xserver. There are no unusual error messages in any of the log files (/var/log/Xorg.0.log, /var/log/messages or any of the log files under /var/log/gdm), which makes this issue a challenge to run down.

SOLUTION:
Running GDM and X on the  Atom Processor D4xx/D5xx/N4xx/N5xx Integrated Graphics Controller requires that you create a file in /etc/X11/xorg.conf.d that I named 10-monitor.conf.

Here is 10-monitor.conf:

Section "Monitor"
Identifier "Monitor0"
EndSection

Section "Device"
Identifier "Device0"
Driver "intel" #Choose the driver used for this monitor
EndSection

Section "Screen"
Identifier "Screen0" #Collapse Monitor and Device section to Screen section
Device "Device0"
Monitor "Monitor0"
DefaultDepth 16 #Choose the depth (16||24)
SubSection "Display"
    Depth 16
    Modes "1920x1080" #Choose the resolution
EndSubSection
EndSection

Change the Modes line to match the resolution of your monitor, of course. That's it.  Problem solved.  GDM loads and Gnome works as expected.