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Re: Call for Testing: Updated Apple backlight driver

 

On Wed, Feb 01, 2012 at 11:38:39PM +1030, Alex Murray wrote:
> On 01/02/12 03:25, Seth Forshee wrote:
> > [Note that I'm not subscribed to the mactel-support-community list;
> >  please Cc me on any replies]
> > 
> > Hi all,
> > 
> > I've been doing some work on the Apple backlight driver in the Linux
> > kernel to get support for adjusting the screen brightness via the gmux
> > device. This will hopefully get working screen brightness adjustment for
> > all Macs that that don't currently have it. This support has been
> > floating around in various forms for a while now, and what I'm trying to
> > do is get it into stock Ubuntu so brightness adjustment will work
> > out-of-the box, more or less.
> > 
> > The driver changes are pretty much complete, and now I'd like to get
> > testing on as many different Apple models as possible. If you've got a
> > machine with a built-in dispaly and would be willing to test, please
> > visit the following page for instructions on how you can help.
> > 
> >   https://wiki.ubuntu.com/Kernel/AppleGmuxBacklight
> > 
> > Thanks for helping! Feel free to contact me if you have any problems
> > with the instructions or encounter any problems with the test driver.
> > 
> > Seth
> > 
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> Hi Seth
> 
> Great to see some more traction on this (I've personally done some work
> on it myself (reverse engineering the need to write out the low
> brightness value bytes then flush to hardware with 0 at highest byte) so
> am glad to see it perhaps make it into mainline - although your version
> looks a lot cleaner than what I was working with - originally derived
> from Matthew Garrett's work... - which is really nice to see.

Awesome, thanks for helping to figure out the interface, and thanks as
well for testing the new driver!

> Anyway, I can confirm it works on my MacBook Pro 5,1 running Oneiric
> booting via EFI (and hence with backlight controlled via gmux) - great work.
> 
> Would be great to see this get pushed into the upstream Linux kernel too
> rather than just carried as a patch in Ubuntu (although I can imagine
> its too late for the Precise kernel now anway).

Yep, the plan is to get this upstream as well. It's unclear at this
point whether I'll be able to get this into Precise at release, but if
not we should be able to get it into an update post-release.

Seth


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