jaunty, not able to change lcd brightness for lenovo ideapad Y450 laptop with nvidia driver

[Jaya]

With original installation of Jaunty using open source driver, the Fn+up-arrow, Fn+down-arrow keys can be used to adjust brightness of the screen. The notification system shows the brightness level change and the actual brightness of the laptop changes properly as well.

But after activating the nvidia proprietary driver, with the Fn+up-arrow, Fn+down-arrow keys the notification system shows brightness change, but the real brightness of the screen is not changed, it always remains at 100%. The file "/proc/acpi/video/VGA/LCD/brightness" seems to get updated with Fn+up-arrow, Fn+down-arrow keys.

Running the script from,
 http://www.thouret.co.uk/blog/2008/12/shell-script-for-linux-nvidia-kernel-module-laptop-brightness-workaround/

seem to work. It is able to change real brightness of screen with this script to any value.

ProblemType: Bug
Architecture: i386
DistroRelease: Ubuntu 9.04
HibernationDevice: RESUME=UUID=67853012-a272-4900-ad4e-c42f1a3c78ac
MachineType: LENOVO IdeaPad Y450
NonfreeKernelModules: nvidia
Package: linux-image-2.6.28-13-generic 2.6.28-13.44
ProcCmdLine: root=UUID=51b80346-f2a4-4605-9152-30ca36254cd4 ro quiet splash
ProcEnviron:
 LANG=en_SG.UTF-8
 SHELL=/bin/bash
ProcVersionSignature: Ubuntu 2.6.28-13.44-generic
SourcePackage: linux

[Ryan Hamilton (rthamilt)]

This affects me too in Karmic. I have backlight control in the entire boot process right up until the nvidia driver starts up, and then afterwards only in a virtual terminal (Control + Alt + F1). Any progress on this?

[Jeremy Foshee (jeremyfoshee)]

Hi Jaya,

If you could also please test the latest upstream kernel available that would be great. It will allow additional upstream developers to examine the issue. Refer to https://wiki.ubuntu.com/KernelMainlineBuilds . Once you've tested the upstream kernel, please remove the 'needs-upstream-testing' tag. This can be done by clicking on the yellow pencil icon next to the tag located at the bottom of the bug description and deleting the 'needs-upstream-testing' text. Please let us know your results.

Thanks in advance.

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