# Sony Vaio VGN-FZ290 backlight dimming and brightness control

## Pseud

I bought this Vaio model recently and immediately proceeded to put the dual core processor through the rigors of a 64-bit Gentoo compile  :Smile:  There are a few things that aren't working yet, but here's the most critical of the lot: backlight dimming. This particular Vaio model has a super-bright screen, which, at full setting, makes me wanna wear sun glasses!

The FN key combos meant for backlight dimming don't work, even with the sony-laptop kernel module (Kernel: 2.6.24-gentoo-r2) loaded. I've searched the forums here and elsewhere, but I can't find a solution that works for the particular combination that I have, viz., an FZ series model with the NVIDIA 8400M GT graphics chip.

The nearest to a solution I have found, and am using right now, is to use the NVIDIA X Server Settings utility and use the X server brightness control function in there. Speaking of which, I have a fundamental question: Is backlight dimming synonymous with brightness control? I believe it is not, but I might be wrong. The reason I suspect they aren't the same is that on Vista (which I can't flush down the drain as yet  :Very Happy: ), the FN key control for backlight dimming and the NVIDIA control for brightness seem to be completely independent. Also, I don't know if my NVIDIA brightness control on low actually helps save power used for the display (as backlight dimming would).

Can someone clarify?

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## WakkaDojo

Not sure if this helps, but it got it working for me:

http://gentoo-wiki.com/HOWTO_sony_vaio_backlight_dimming

Good luck!

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## Pseud

I've tried that, but unfortunately, it doesn't work for the FZ series.

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## Pseud

Um, could anyone clarify at least the bit on whether backlight dimming and brightness control are one and the same?

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## eaglex

Hello,

I have the same issue with an AR series vaio. No solution here either, so far.

I don't think dimming == brightness. It just doesn't feel like the same thing.

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## eaglex

In case you haven't already found the fix, see: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/95444 .

A patched nvclock was posted that works with 8 series nvidia graphic cards.

Yay.

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## Pseud

Thanks eaglex!!

I tweaked the beta3 ebuild on gentoo bugzilla to include the patch file mentioned in the discussion thread you pointed out (thanks to neilsslot in the thread there for creating and posting a link to the patch file). It's in my portage overlay now and works great  :Smile: 

I'm now gonna get greedy and try to get the Fn keys to do this, instead of doing nvclock -S xx from the command line

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