This is not a driver issue. Its just that you have got to make xrandr changes permanent. I just had a similar problem and solved it by the method shown here . I will explain it below.
First, create a shell script with the commands you have given in your description as shown below:-
#!bin/sh
xrandr --newmode "1280x1024_60.00" 109.00 1280 1368 1496 1712 1024 1027 1034 1063 -hsync +vsync
xrandr --addmode VGA1 "1280x1024_60.00"
xrandr --output DisplayPort-0 --off --output VGA1 --mode 1280x1024_60.00 --pos 0x0 --rotate normal --output HDMI-0 --off
(You may have to edit the last line according to your system specs.) Save it as lightdmxrandr.sh in /usr/bin . Make it executable by running :-
sudo chmod a+x /usr/bin/lightdmxrandr.sh
Now just try running it from your terminal to see if it executes without errors :-
sudo sh /usr/bin/lightdmxrandr.sh
If it runs right, you have to make some edits to /etc/lightdm/lightdm.conf . For that open it with nano :-
sudo nano /etc/lightdm/lightdm.conf
You can even use gedit or whichever text editor you prefer. It will be something like this :-
[SeatDefaults]
user-session=ubuntu
greeter-session=unity-greeter
Now add the following lines to it:-
display-setup-script=/usr/bin/lightdmxrandr.sh
session-setup-script=/usr/bin/lightdmxrandr.sh
This should most probably work for you and you must get your desired resolution both in your desktop and login screen. But some users like myself had a problem because of which the login screen resolution would change but the desktop resolution would not, when the above is done. If that is the case, drop into a terminal or tty session(If you had login problems after attempting the above) and type in :-
sudo nano /etc/lightdm/lightdm.conf
and then remove the lines we added to it above. Then reboot successfully and follow the below instructions.
Now, first go to System Settings>Displays and see if your desired resolution is there. This might happen since you just ran the above script with lightdm.conf . If it is so then select it. Then reboot and see if it works. If your desired resolution is not there even now, then attempt the following.
Open "Startup Applications" by searching for it in the dash. You will get something like this :-
Then,
- Select the Add button.
- In the subsequent window type in a name.
- Then select the /usr/bin/lightdmxrandr.sh which is the script we created.
- If you want you can give a description. Then click Add.
- Make sure the entry you just added has a tick mark next to it. Now close Startup Applications.
Now reboot and you must have your resolution in your desktop alone. To change your login screen resolution too again open lightdm.conf file in the same way as mentioned above and add the below line alone:-
display-setup-script=/usr/bin/lightdmxrandr.sh
Save it and reboot. Now you will have both your desktop and login screen resolution for sure.
PS :- If /etc/lightdm/lightdm.conf is not present in your system then edit /usr/share/lightdm/lightdm.conf.d/50-ubuntu.conf .