在安裝beryl 和 Nvidia 官方驅動的時候並沒有清除原來的舊驅動，也可能是
This confuses nvidia-installer into thinking that your X server is very old and it installs the X modules in the wrong place. To work around this problem, use the following options:
# sh NVIDIA-Linux-version.run --x-module-path=`X -showDefaultModulePath 2>&1 | cut -d, -f1` --x-library-path=`X -showDefaultLibPath 2>&1`
總之，症狀為每次重啟電腦都需要重新編譯 Nvidia 驅動才能進入 GDM（x win）。錯誤日志內容為：
Error: API mismatch: this NVIDIA driver component has version 100.14.11, but the NVIDIA kernel module's version does not match.Please make sure that the kernel module and all NVIDIA driver components have the same version.
我做了如下步驟（不是很清楚到底是那步起了作用還是都需要，你自己參考）
sudo apt-get remove nvidia-glx --purge
完全刪除 nvidia-glx
刪除 /etc/init.d/nvidia-glx 和 /etc/init.d/nvidia-kernel
修改 /etc/default/linux-restricted-modules-common 文件，加入
DISABLED_MODULES="nv nvidia_new"
我覺得很可能這步才是關鍵的！
倒霉的是我的聲卡是 Conexant（nVidia Corporation MCP51 High Definition Audio），於是乎，聲音沒有啦...
可以參考此文，部分內容如下：
the nvidia-glx package has been uninstalled with the --purge option and the files /etc/init.d/nvidia-glx and /etc/init.d/nvidia-kernel do not exist
You need to delete the legacy driver within /lib/modules directory
once you delete those, then install the nvidia drivers, and you'll be ok.
If you use Ubuntu, please also ensure that the linux-restricted-modules or linux-restricted-modules-common packages have been uninstalled. Alternatively, you can edit the /etc/default/linux-restricted-modules or /etc/default/linux-restricted-modules-common configuration file and disable the NVIDIA linux-restricted kernel modules (nvidia, nvidia_legacy) via:
DISABLED_MODULES="nv nvidia_new"
Additionally, delete the following file if it exists:
rm -f /lib/linux-restricted-modules/.nvidia_new_installed
Please note: unfortunately, it has become difficult to keep track of the pre-/post-installation steps required for [K]Ubuntu, and the above instructions may be incomplete. If in doubt, it is recommended that you use your distributor's NVIDIA Linux graphics driver packages, exclusively.
