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How to troubleshoot Screen resolution problem in Ubuntu

Linux users come across a common problem in which they dont find their native monitor resolution and instead they left with the default resolution of 1024*768. This is because the system couldn’t identify the graphics card driver.

Don’t worry, with simple steps you can add your own desired resolution and make the changes permanent in your system even when the “displays”  menu says “unknown” monitor.

Step 1

Type the following command in your terminal to know the resolutions available in your system

 

xrandr

  • Your current resolution will be marked by ‘*’.

Step 2
  • Now that you identified the resolutions available its time to add your own desired resolution.
  • For example, if you want to add the resolution of 1280*1024 type the following command in terminal,

 

cvt 1280 1024 75 (75 denotes the refresh rate in Hz).

  • You will get modeline with many paramaters which will look like,

Modeline "1280x1024_75.00"  138.75  1280 1368 1504 1728 1024 1027 1034 1072 -hsync +vsync

Step 3

Next, the new resolution mode can be created using the below command and press Enter

 

xrandr –newmode "1280x1024_75.00"  138.75  1280 1368 1504 1728 1024 1027 1034 1072 -hsync +vsync

Now you can check the new mode by typing the command,

xrandr

Step 4

Next, the new mode should be added to list of native resolutions by the command,

 

xrandr --addmode VGA1 "1280x1024_75.00"

    • Type the command to check if the resolution is added.

xrandr

Step 5

Before you can mess up with the xorg.conf file which will be explained in step 6 you need to have some details in your hand like,

 

Identifier, for example Identifier  "Screen0"
Device,    for example  Device    "Device0"
Monitor,  for example Monitor    "VGA1"
Driver,     for example Driver      “ i915”

  • Mostly identifier and device name can be obtained from “displays” option from “dash home”
  • While monitor can checked using xrandr and driver information can be obtained using the command,

sudo lshw -class display|grep "driver"

Step 6

Now that you have the essential details in hand its time to make the changes permanents by editing xorg.conf file available in the location /etc/X11/xorg.conf.

To achieve this, type the following command in terminal,
sudo gedit /etc/X11/xorg.conf

Some of you would get error executing this command because here gedit indicates the text editor(like notepad) with which you are editing the xorg.conf file. So, if you are using someother text editor as default just replace gedit with it.

Don’t forget to enter your administrator password and press Enter.

Type the following in the editor,


Section "Monitor"

Identifier    "VGA1"

Modeline "1280x1024_75.00"  138.75  1280 1368 1504 1728  1024 1027 1034 1072 -hsync +vsync

EndSection

Section "Screen"

Identifier     "Screen0"

Device         "Device0"

Monitor        "VGA1"

SubSection "Display"

Modes      "1280x1024_75.00"

EndSubSection

EndSection

Section "Device"

Identifier    "Device0"

Driver        "i915"

EndSection

  • Save and close it.
Step 7

The final step is setting the mode you created as active. To achieve it type the following command,

 

xrandr –output VGA1 –mode 1280x1024_75.00

Press enter and your screen resolution is changed.

If you get a error message “xrandr: cannot find mode 1280*1024_75.00” , the problem is with the “*” you entered so enter as 1280x1024_75.00 and not  1280*1024_75.00.

Feedback

Hope you enjoyed reading this article. We are a bunch of Linux (Ubuntu) users trying to guide you on fixing problems or on customizing Linux. If you want any particular topic to be discussed here, do let us know via comments.


- has written 5 posts on Smashing Tips


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