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I am trying to get the LCD backlight brightness control to work properly on my new ASUS G75VW-DH72 laptop in Ubuntu 12.10. I got it to mostly work by following the instructions that I wrote here (acpi_osi=Linux acpi_backlight=vendor, EnableBrightnessControl=1). However, there are still two issues:

The main issue is that I have to press the hotkey (fn+F5 or fn+F6) TWICE before there is any effect on the brightness, or any output in the acpi_listen command. So if I run acpi_listen and press fn+F6 six times, the output only has three lines:

video LCDD 00000086 00000000
video LCDD 00000086 00000000
video LCDD 00000086 00000000

What causes this? How can I fix it? This behavior doesn't happen in Windows.

(Also, I noticed that the brightness is incrementing/decrementing in steps of 2 instead of 1, unless I happen to have a menu open. Any advice on that is welcome.)

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I was do the same as above. Then I had to Text my g75VW and closed the lid.

I come back after a while then I opened the lid and then the backlight was working with F5/F6 as it should be…

Only the onscreen display not showing…

I tried again with lid closing and after a while open it and it still working..

Hope it's helps.

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Interesting. So it's working for you now? Can you run acpi_listen and tell me what you get when your press the Fn+F5 four times followed by Fn+F6 four times? Are you using the nvidia proprietary driver or nouveau (lsmod | grep nou)? – David Grayson Dec 17 '12 at 19:08

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