Today, there are many problems with the graphics card driver. One of them is that after the computer restarts, the resolution of the display screen becomes 800600, and the normal resolution is 19201080. There is no other resolution option in the system settings, so it cannot be modified. Try to create the xorg. Conf file, which is described on the Internet, to set the custom desktop resolution. After the modification, the resolution has changed, but it is 1600 * 1200, which is still very abnormal. Using the combination of CVT and xrandr to modify the resolution indicates another error, xrandr: failed to get size of gamma for output default. One problem after another, what a tangle!

It has to be said that it’s really unpleasant to search these professional problems with Baidu in China. What often appears are some irrelevant or unsolvable web pages. Fortunately, it’s all solved now, and the problem is still in the driver side of the graphics card [1]. Software & amp; update in system settings; In updates, click additional drivers and change it to NVIDIA driver (I choose the third one here, as shown in the figure below). The application modification needs to wait for a little time, restart the computer after completion, and the resolution is normal again.

After the driver is re installed, the problem of circular login appears again. You may encounter it later. Record the solution here.

ctrl +alt +f2  
sudo service lightdm stop  
sudo apt-get --purge remove nvidia-*  

After many months, I stepped on the big pit of circular login again, but the previous solution was invalid. Another possible problem is that the owner and all groups of the. Xauthority file become root. There is a. Xauthority file in the user’s home directory. View the owner and all groups of the file

ls -la .Xauthority

If it is root, you need to change it to your login user:

sudo chown username:username .Xauthority

(there will always be all kinds of accidents in the actual solution, one by one, don’t worry.)