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I recently installed ubuntu 13.04 (kernel 3.8.0.y) on an older Asus UL30vt laptop. This is a switchable graphics (optimus) laptop with a intel onboard graphics card and an Nvidia Geforce G210M. I am running bumblebee on the laptop, so the active graphics card is the intel one.

All other fn keys work, but only the volume-up and volume-down keys bring up the on-screen display.

There are a variety of Linux help pages for this laptop online (including https://wiki.ubuntu.com/AsusUL, http://wiki.daviddarts.com/Ubuntu_Lucid_on_the_Asus_UL30VT#Screen_Brightness, https://wiki.debian.org/InstallingDebianOn/Asus/UL30VT) but they seem to rely on scripts that don't exist anymore. For example, as far as I know, the asus-wmi dkms modules were included in kernel 3.8 and should not be necessary.

I am unable to adjust the backlight using

xbacklight -set X 

where X is a value between 0 and 100. The command runs without complaints, using e.g. xbacklight -set 0, but the backlight intensity does not change.

I have tried a variety of grub boot parameters, including testing all of the following in turn:

acpi_osi=, 
acpi_osi=Linux, 
acpi_osi='!Windows2012', 
acpi_backlight=vendor, 

but with no improvement. I also tried using both acpi_osi=Linux and acpi_backlight=vendor at the same time, with no improvement.

Thus far, I have only found one way to change the screen backlight:

sudo setpci -s 00:02.0 F4.B=XX 

where XX is a value between 1a and ff (hexadecimal).

I have found a linux kernel note that there is a change in a new kernel related to this laptop and the backlight: http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=c8f6d8351ba8c89d5cd4c562552ec7ec29274e31 However, this code forces the vendor driver, which might be the same as using acpi_backlight=vendor which did not work.

I'd appreciate any help.

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Same problem on UL80vt. I have reported a bug on launchpad at bugs.launchpad.net/ubuntu/+source/linux/+bug/1178796. –  guimillet Sep 12 '13 at 0:13
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