I cant change the brightness of my fedora 16

[rakux]

i have an acer 5755g i cannot change the brightness of the lcd.....i tried re installing bash but that didnt work.......when i use the brightness keys(fn+fwd,bkwd) i can see the brightness bar goin up and down but no change in brightness.......my laptop uses nvidia optimus technology,i dont know if that is a problem
i tried changing it from system setting also and it didnt work

im a beginner some posts ive seen on this issues were too technial for me

need help

[JamesNZ]

Optimus has virtually no support for linux, you'd be better off getting another GPU. But try this anyway (as root):

echo 4 > /sys/class/backlight/acpi_video0/brightness

If that works, the screen brightness should change. You adjust the brightness by changing the '4' to another number such as 5 or 3.

[rakux]

The code you gave does the same thing the brightness keys do, it changes the value of brightness(the brightness bar is lowered) but the actual screen brightness remains maximum.......is there a way to hard code this value by changing some config files.....itd be ok if the brightness remains a lil less but now reading is stressful

[rakux]

there is support for optimus on linux.....i found the properitery drivers but the fedora install is very complicated

[MikeTbob]

Do you have a link? It's kinda hard for you to post links but steer us in the right direction and we may be able to help you along.
Post the link but you'll need to remove the http:// part, just post the actual link like so.
http://www.linuxforums.org/forums
would be made to look like this

linuxforums.org/forums

[rakux]

there is an easy way for optimus also now

[link]forums.fedoraforum.org/showthread.php?t=204752[/link]

my video card is listed in supported devices--> geforce gt 540m (this is optimus)