Apple MacBook backlight brightness doesn't work

Hi Ryan!

So what are your magic runes to get backlight control working on the MacBook?

Thanks in advance! *hug*

Hi Martin

I'm more or less using what I describe on that page.

I'm working on a better solution for the longterm. Maybe I'll get some time to hack on it this week at the conference..... (I wouldn't be suprised if I don't, though) :)

I'll keep you posted.

Hi,

There is also in feisty the program pommed which lets you change backlight brightness with F1 and F2 keys. But I don't think it uses hal.

Hi Martin

Patch is written and has been sent upstream. David has said that he will try to make a release in the coming weeks, so should be good to go for feisty.

Cheers

Thanks, Ryan! Will grab the patch.

It turns out that on suspend/resume, the backlight control register is clobbered to all-zeros.

The only way to fix this is to use vbetool to save/restore the BIOS state. This is currently broken on the macbook due to the init scripts being out of order (vbesave runs before acpid, and on macbook this causes vbesave to fail to detect that we're a laptop).

There is, however, another fix. The attached program (which is a hackish modification of part of the patch submitted upstream) will reset the value of the register. This seems to be sufficient to get the card working properly again (ie: no need for a full vbetool state restore).

Link with -lpci.

This code needs to be somewhere -- be it in the kernel, the X server, HAL or the system resume scripts -- but only run for Macbooks. I'm guessing that for now, HAL or "system resume scripts" is the easy answer.

Also: to do this properly we should probably look at the value of the backlight at suspend, save this value, then write the same value back on resume. The current code just sets to max value on resume.

David is currently romping around in the aussie outback. I'll try to nail him down to find out what he thinks :)

In bzr

 hal (0.5.8.1-4ubuntu9) feisty; urgency=low
 .
   [ Sebastian Dröge ]
   * debian/patches/62_dbus-python-0.8.patch:
     + Correctly show HAL properties in hal-device-manager with dbus-python
     0.80. https://bugs.freedesktop.org/show_bug.cgi?id=9343
 .
   [ Matthew Garrett ]
   * debian/patches/63_fixup_macbook_pro.patch:
     + Fix building the MBP addon, and edit the FDI files so it binds to new
     hardware.
   * debian/patches/64_macbook_backlight.patch:
     + Add support for the backlight on Macbooks.
     https://launchpad.net/ubuntu/+source/hal/+bug/72287
 .
   [ Martin Pitt ]
   * Add debian/patches/62_ignore_single_slash_label.patch: Ignore labels which
     only consist of a slash, so that they do not end up as /media/-.
     (LP: #83323)
   * debian/patches/30-mp3-player-fdi.patch: Add Sony Ericsson W300i.
     (LP: #86866)
   * debian/patches/30-mp3-player-fdi.patch: Add Transcend T.Sonic 520.
     (LP: #90117)

Thanks, Matthew!

I am running a fully updated Gutsy install on a non-pro MacBook and the brightness controls are not working here.

Martin, your bug is different: Bug 119184

Stefano, the bug he is referring isn't that one either. The keys work (as in send the events) but the brightness level gets stuck on the minimum. Considering the keys work and g-p-m can adjust the brightness (even from the applet) what can be the problem here?

Hi,

today I was installing gutsy tribe 4. I upgraded it to new staff from repositories. And my backlight on macbook don't function. I have black macbook first generation. And It is behave strange, cause I can decrease it but when I want increse it increse only one unit and on next it goes one unit down. It is really strange.

I have latest - and it still doesnt work. As I wrote to comments.

Hello Whisky, this isn't the same issue. This one was related to missing rules in hal fdi files for newer models recognition. Our problem right now has to do with something else, I believe. So this bug is solved, hal supports our hardware. Can it be g-p-m?

Do other laptop models work well? I get the same behavior as Whisky on a Macbook C2D.

Maybe you are right, do you think that we should make new bug? Maybe it's a good idea!

I think someone already did:
https://bugs.launchpad.net/ubuntu/+source/gnome-power-manager/+bug/123548

:)

On Tue, 2007-08-21 at 16:51 +0000, Whisky wrote:
> Maybe you are right, do you think that we should make new bug? Maybe
> it's a good idea!
>