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I think something changed in maybe the Linux core which has broken Ubuntu and practically every other Linux install on my laptop.

The problem is that suddenly the back-light doesn't work when I run Ubuntu. This means that I can faintly see the Ubuntu login screen but as the screen isn't emitting light its impossible to use.

There is a way I can use it. If I jump into the - grub? - menu when pressing shift on start up I can choose a previous version of Linux / Ubuntu and it all runs fine. Unfortunately... without doing that it doesn't work.

I have tried a variety of installs including Kubuntu - I thought this had a different display or GUI thing but no dice.

Has anyone heard of this happening to other people? Is there a fix around?

Its an emachines E525 laptop.

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Are you sure that the problem is operating system related? If your laptop is old, your screen back-light might be problematic. – Mustafa Zengin Jul 17 '11 at 19:43
@JasonS, can you provide us with a couple specific GRUB entries to show us what works and what doesn't? If it's kernel-related, that might help. – WarriorIng64 Jul 17 '11 at 20:13
Mustafa - Yes. 10.10 works fine. It was only when upgrading to 11.04 that this occured. – JasonS Jul 18 '11 at 17:45
Warrior - Sorry. I don't know. I tap shift. I get a little menu. I select Previous Versions. I then have 2 options. Previous version or Previous version safe mode. This works. If I run Ubuntu without selecting previous version the problem above occurs. – JasonS Jul 18 '11 at 17:47

1 Answer

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I've had a similar problem - it's a problem caused by one of the changes to the kernel, although I'm not sure where this is located in the kernel configuration menu. {Presumably one way of solving it would be to track down the source of it in the kernel config menus and recompile the kernel with the offending feature deselected.}

A quick fix solution is to use the command

sudo setpci -s 00:02 F4.B=0

which tells your computer to restore power to the backlight. I appreciate that it's a bit difficult to open up a terminal window if you can't see what you're doing, so you might want to set a keyboard shortcut like Ctrl-T to open a terminal. Hope this helps.

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