Thursday, December 08, 2011

Solve Unknown Monitor (or Monitor not Detected) in Ubuntu 11.10

If you have the same problem as the title of this post, Ubuntu unknown monitor or Monitor not detected in Ubuntu 11.10, hope this tweaks help you. Previously, I upgraded my 11.04 Ubuntu to 11.10. No problems appear except can be solved as I post in GNU/Linux label in this blog. Yesterday, I got the problem after running some tweaks and computer janitor (maybe that caused the  problem). My screen or display resolution is changed to lower resolution, i.e 1024x768.

Then, I try to change manually trough display configuration. What I get is my monitor not detected by Ubuntu. It said unknown monitor. I run xrandr in terminal, and got the following output
$ xrandr
xrandr: Failed to get size of gamma for output default
After a day find solution, below is work for me. Find the similar code in your /etc/boot/grub.cfg. For example, type in terminal: sudo gedit /etc/boot/grub.cfg
linux    /boot/vmlinuz-2.6.32-26-generic root=UUID=c3732ca6-61fa-48c6-b115-6ed668cdeedd ro ...
Add the "i915.modeset=1 gfxpayload=1366x768". So, it becomes
linux    /boot/vmlinuz-2.6.32-26-generic root=UUID=c3732ca6-61fa-48c6-b115-6ed668cdeedd ro i915.modeset=1 gfxpayload=1366x768 quiet splash
And reboot. It works for me, and I hope also for you. Don't forget to change screen resolution according to your display size. The  figure below show the difference when I got the problem and after solving it.
My laptop display when got unknown monitor problem.
The screen resolution is low i.e 1024x768
My screen after solving the problem with 915 driver. I  looks clear
Note that the problem above is caused by VGA driver which disappear unfortunately. So, I add 915 driver on boot based on reference from internet source.

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