mactel-support-community team mailing list archive

[Seth Forshee <seth.forshee@xxxxxxxxxxxxx>]

On Tue, Jan 31, 2012 at 12:48:43PM -0600, tjbarber09@xxxxxxxxx wrote:
> > 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.
> 
> Wonderful! Thanks for all the hard work. I'm going to install this an see
> if it works on my MacBook Pro 5,5. I've had to deal with full brightness at
> 5AM in the morning and it's starting to kill my eyes. ;P
> 
> 5 minutes later:
> 
> Seth, you are my hero for the day. On the MacBook Pro 5,5 I have full
> control of my display's brightness. However, we have a strange issue
> here... When I run:
> 
> ls /sys/class/backlight
> 
> All I get is:
> 
> nvidia_backlight
> 
> Which is really strange... I had nvidia-bl-dkms installed from natty but it
> never worked. So I remove it and reboot. Nothing. I can't adjust the
> backlight. I reverse it and install nvidia-bl-dkms and remove
> apple-bl-gmux-dkms. Still doesn't work. Reinstall both and everything is
> good. So what gives? I don't see the directories gmux_backlight,
> acpi_video0, or apple_backlight. What form of magic is this? =P

I'm not sure what's going on here without looking at the source for the
nvidia-bl-dkms package, which I'll do when I get a chance. The
apple-bl-gmux-dkms package isn't actually controlling the backlight,
it's just having some strange side effect that seems to make the
nvidia-bl-dkms driver start working.

Seth