Hi,
I have just installed Ubuntu 10.04 LTS 32 Bit on my Compaq Presario CQ40 616TU laptop. My screen flickers (Horizontal Line flicks) in few second interval when running on battery power. This is really annoying.

Here are the details:
1. Issue occurs when running on battery power and is reduced(with a little flickering at bottom of the screen) or almost gone when connected to AC power adapter.
2. The screen also flickers while booting. However it is maximum on battery power.
3. I use Compaq CQ40 616-TU laptop with Intel Graphics Media Accelerator 4500 graphics.
4. I tried Mandrive One Spring 10 and also experienced the same problem.

I changed the Grub file and added i915.powersaver=0 but it did not work. However if I use the laptop with high brightness the problem is reduced (with a little flickering at bottom of the screen) or gone.

I am new to linux and any suggestion is highly appreciated.

Thanks
Bishnu

Can you determine whether this is a software or hardware problem (for instance, does it do this when you let the computer sit at the BIOS screen?) Firstly, I'd recommend that you press Break when your PC first turns on and then see if the screen sits still on battery power specifically (but you can use your AC adapter if you want.) When you've observed it and let it sit for a minute or so, you can press power. If it flickered while on the BIOS splash, Linux hasn't even loaded yet, and it's a hardware issue. If this only happens once the PC boots, then you know it's a software issue.

- If a hardware problem (it almost sounds like it might be), then you need to have your flat panel (screen) serviced. Or you can take the lid off, and put a new screen in.

- If not, and you're sure of it, it may be a conflict with the settings in /etc/X11/xorg.conf. If you do not have such a file, you can (with the distro you're running), find settings online that are tailored to your hardware, and paste it into the file. You can do this by:

1) Opening a shell and typing in sudo vi /etc/X11/xorg.conf, and then pasting the text will work, though nano will work, too.

2) Type gksu gedit /etc/X11/xorg.conf and paste it (you might find the GUI easier if you don't like the shell) Substitute gedit with a text editor you have installed (e.g. kate, mousepad, leafpad, etc.) if you need to.

Hope everything gets fixed.

Thanks for the reply.
Actually lately I discovered that this is a hardware Issue with my laptop screen.
I have given this for service at HP service center.

I hope that was not a problem due to ubuntu (Comments required.).