Take the 2-minute tour ×
Ask Ubuntu is a question and answer site for Ubuntu users and developers. It's 100% free, no registration required.

I have a Lenovo y410p, and I am trying to install Ubuntu 13.10 in EFI mode side-by-side with a Windows 8 installation on a GPT partition. I have already disabled secure boot, and I have the LiveCD image running off a USB flash drive in EFI mode.

When I get to the GRUB environment, I have to modify the kernel arguments to put nomodeset=1 or the screen will be turned off when the kernel starts.

lsmod shows that the following modules are loaded for video:

i915
nouveau

The former is just the usual Intel graphics driver, and the latter is the open source NVIDIA driver.

When X starts, in /etc/X11/Xorg.0.log it reports that a screen was found but it was not properly configured, and then it shows "no screens found".

Starting with nomodeset=1 in Install Ubuntu instead of Try Ubuntu works fine.

After installation, the same issue occurs as on the live environment. No dice. Not sure where to go from here.

share|improve this question
add comment

1 Answer 1

The reason the screen was showing up black was because KMS (Kernel Modesetting) wasn't turning on the backlight for the Intel-backed screen. In Optimus, the Intel device gives the image to the screen device, and the NVIDIA device simply acts as a pixel buffer generator and is not actually attached to the screen.

Open /etc/rc.local and add the following line before exit 0

setpci -s 00:02.0 F4.B=30

The 30 may be changed to any value between 00 and FF. 00 is Full Bright, FF is Full Dark.

Source: http://askubuntu.com/a/157344/246852

share|improve this answer
add comment

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.