You can also use a framebuffer driver (vesafb) but then the display  
might not get restored and then you would need to guess when to  
reboot. I would wait lets say 2 minutes when doing it this method and  
then reboot (just by typing it into another VT)

Quoting Bem Jones-Bey <email address hidden>:

> On 01/28/2009 11:29 AM, Thunderbird wrote:
>> What might be useful is the following on a fresh boot of your system
>> without using the nvidia driver and also without a framebuffer driver
>> (a framebuffer driver could prevent an image restore).
>>
>>
> Does Ubuntu have a kernel that doesn't have a framebuffer driver, or
> would I have to compile my own? (Or does it not load the framebuffer
> driver when I boot single user?) And I guess the other option would be
> to boot with one of the minimal Linux distros.
>
> --
> No Screen Backlight Control; Notebooks (Vaio, Macbook, HP/Compaq,   
> Samsung, Zepto et al.)  with Nvidia Geforce8/Geforce9/Quadro series   
> graphics
> https://bugs.launchpad.net/bugs/95444
> You received this bug notification because you are a direct subscriber
> of the bug.
>
> Status in Hardware Abstraction Layer (HAL): Invalid
> Status in “hal” source package in Ubuntu: New
> Status in “hotkey-setup” source package in Ubuntu: In Progress
> Status in “linux” source package in Ubuntu: In Progress
> Status in “nvidia-graphics-drivers-177” source package in Ubuntu: In Progress
>
> Bug description:
> Using Ubuntu on laptops with Nvidia Geforce8/Geforce9/Quadro vga card:
>
> On various laptops from Sony, HP, Samsung and others there is no way  
>  to control backlight brightness. In case of Sony e.g. on Vaios with  
>  8-series adapters, e.g.
> nVidia Corporation GeForce 8400M GS
> nVidia Corporation GeForce 8600M GT (rev a1)
>
> The registers have been found (kudos to mikes!) and incorporated into
> nvclock, which you can check out by anonymous cvs and install:
>
> ]$ sudo apt-get install cvs
> ]$ cvs   
> -d:pserver:<email address hidden>:/cvsroot/nvclock   
> login
> ]$ cvs -z3   
> -d:pserver:<email address hidden>:/cvsroot/nvclock co  
>  -P nvclock
> ]$ cd nvclock
> ]$ ./autogen.sh
> ]$ ./configure
> ]$ make
> ]$ sudo make install
>
> To test, make sure you are using nVidia's proprietary driver, then:
> ]$ sudo nvclock -S 100
> ]$ sudo nvclock -S 15
> ]$ sudo nvclock -S +10
>
> So far mikes' registers have been found to work on:
>
> Apple laptops
> {
> Macbook 5,1 Aluminum 13.3"  (Geforce 9400M)
> }
>
> HP/Compaq laptops
> {
> 8510W (Quadro FX 570M, MXM)
> 8710P (Quadro NVS 320M, MXM)
> }
>
> Samsung laptops:
> {
> Q210 (Geforce 9200M)
> Q310 (Geforce 9200M)
> R510 (Geforce 9200M)
> }
>
> Sony laptops:
> {
> 8400M GS:
> VGN SZ650N, SZ61MN/B, SZ730E, SZ750N, SZ71MN/B, SZ71E
>
> 8400M GT:
> VGN FZ38M, FZ31M, FZ11Z, NR31, AR41E, FZ11S, FZ290, FZ250AE, FZ21E,   
> FZ21M, FZ21S, FZ470E, FZ340E, FZ190N, FZ18M, FZ31E, FZ18E, FZ260E   
> NR21Z, NR38S, NR21S
>
> 8600M GS:
> VGN FZ31Z, FZ21Z, FZ31S
>
> 8600M GT:
> VGN AR51SU, AR71S
> }
>
> Zepto laptops
> {
> Geforce 9600GT based laptops using MXM cards
> }
>
> Add your model to the list by clicking on the "Update description /   
> tags" link, NOT by asking in a bug comment for someone else to do it.
>
> To get hotkeys to work, follow the instructions in this comment:
> https://bugs.launchpad.net/ubuntu/+source/hotkey-setup/+bug/95444/comments/75
> or install the package at :
> https://bugs.launchpad.net/ubuntu/+source/hotkey-setup/+bug/95444/comments/111
>
> Dual-adapter models (SZ6 among others) can get backlight control   
> with the Intel adapter using xbacklight, and can get hotkey   
> functionality as per bug #173652.
>