不知道從哪裏找到的這個方案，反正是能解決了這個問題：
重新升級了CUDA以後，發現在安裝CUDA8.0後，分辨率變成800×600，而且不能改變，最終在網上找到了這個方法，運行下面幾行代碼，然後重啓就好了，具體原因還是不是很清楚。
sudo mv /etc/X11/xorg.conf /etc/X11/xorg.conf.backup
sudo touch /etc/X11/xorg.conf
sudo reboot下面是錯誤信息，在重新安裝完成顯卡驅動後，進入桌面，會出現下面的錯誤：
Could not apply the stored configuration for monitors
none of the selected modes were compatible with the possible modes:
Trying modes for CRTC 63
CRTC 63: trying mode 640x480@60Hz with output at 1366x768@60Hz (pass 0)
CRTC 63: trying mode 640x480@60Hz with output at 1366x768@60Hz (pass 1)
Trying modes for CRTC 64
CRTC 64: trying mode 640x480@60Hz with output at 1366x768@60Hz (pass 0)
CRTC 64: trying mode 640x480@60Hz with output at 1366x768@60Hz (pass 1)
Trying modes for CRTC 65
CRTC 65: trying mode 640x480@60Hz with output at 1366x768@60Hz (pass 0)
CRTC 65: trying mode 640x480@60Hz with output at 1366x768@60Hz (pass 1)
Trying modes for CRTC 66
CRTC 66: trying mode 640x480@60Hz with output at 1366x768@60Hz (pass 0)
CRTC 66: trying mode 640x480@60Hz with output at 1366x768@60Hz (pass 1)