Ubuntu 18.04 dual screen don't work after reboot

Question

I have Dell Optiplex 3020 desktop. I have dual screen setting. Main screen is connected to HDMI and second smaller monitor is connected to VGA. System don't see all resolutions available for VGA (only up to 1024x768). I know how to fix that- i put in console: xrandr --newmode "1440x900_60.00" 106.50 1440 1528 1672 1904 900 903 909 934 -hsync +vsync and then: xrandr --addmode VGA-1 1440x900_60.00

Then I configure everything in settings. Everything seems to work ok. I restart PC- GRUB by default is displayed on my HDMI screen, splash screen too. After I give my password screen (HDMI) goes off and I see only things on screen VGA in resolution 1024x768, all changes done by me seems to be forgotten by system.

Answer 1

I found solution. First I run command to get the mode for my screen resolution- in that case it's 1440x900:

cvt 1440 900

output is in my case:

# 1440x900 59.89 Hz (CVT 1.30MA) hsync: 55.93 kHz; pclk: 106.50 MHz
Modeline "1440x900_60.00"  106.50  1440 1528 1672 1904  900 903 909 
934 -hsync +vsync

I copy starting from "1440x900_600" and to the end. Then I add mode by commands:

xrandr --newmode "1440x900_60.00" 106.50 1440 1528 1672 1904 900 903 909 934 -hsync +vsync

and

xrandr --addmode VGA-1 1440x900_60.00

Since now I can set that resolution for my screen. But that do not work after restart, so I made simple script. I put that script in ~/.config/autostart/ folder (you can name it dualscreen.sh) and it looks like that:

#!/bin/bash

xrandr --newmode "1440x900_60.00" 106.50 1440 1528 1672 1904 900 903 909 934 -hsync +vsync

xrandr --addmode VGA-1 1440x900_60.00

#after that line it is not neccessary
sleep 1s
xdotool mousemove 2400 550

Last two lines are here to move mouse pointer to my main screen (try values which will be ok for you). You need to install xdotool by:

sudo apt-get install xdotool

There is sleep 1s which makes 1 second delay before executing last command, otherwise mouse was moved only to the edge of second screen (by default mouse pointer started on second screen).