Laptop backlight off on log on screen

[Guest]

Ref: http://www.kubuntuforums.net/showthr...l-Based-Laptop

I've had a similar issue (I believe). I've been using Kubuntu for years but when I bought a new laptop with an Intel card and tried to install I would get a black screen. After trial and error I discovered that it was not that the screen wasn't working but that the backlight/brightness was completely off. If I type my login password into the black screen, KDE boots up perfectly and works just fine. I've been using my laptop like this for over a year and I was hoping that the upgrade into 12.04 would fix this but it didn't. Do you think a correction of my /etc/default/grub would help?
Here's what it has right now:

GRUB_DEFAULT=0
GRUB_HIDDEN_TIMEOUT=0
GRUB_HIDDEN_TIMEOUT_QUIET=true
GRUB_TIMEOUT=10
GRUB_DISTRIBUTOR=`lsb_release -i -s 2> /dev/null || echo Debian`
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"
GRUB_CMDLINE_LINUX=""

[doctordruidphd]

First thing I would do, if you are having problems, is get rid of the splash screen.
Change the "quiet splash" to "nosplash"
Not as pretty, but it might give you useful information.
Next, I would specify some graphics mode for bootup.
Try adding these lines:

GRUB_TERMINAL_OUTPUT=gfxterm
GRUB_GFXMODE=1024x768

Don't forget to run sudo update-grub after making the changes.

Beyond that, it may be an intel-chip specific issue, and as I don't have one, I can't offer specific advice for it. Maybe others can.

[oshunluvr]

Try adding this to the LINUX_DEFAULT line:

acpi_osi=Linux acpi_backlight=vendor