nvidia-bl-dkms 0.15.1 update breaks backlight

[Etienne Perot]

Since February 1st's 0.15.1 update of the nvidia-bl-dkms package, the backlight of the screen cannot be changed.
This happens on my Macbook Pro 5-3 but also happens to the 5-5 model according to http://ubuntuforums.org/showthread.php?p=8756152 , so it doesn't seem very far-fetched to say that might happen to all Macbook Pros.

Downgrading nvidia-bl-dkms to version 0.15 makes the screen backlight slider "slidable" again but it has no impact on the screen's actual backlight.

Using Kubuntu 9.10 64-bit on a Macbook Pro 5-3 with kernel 2.6.31-17-generic (but it does the same on the previous kernels as well).

[Michel Roche (pichel)]

Hello,
seen the same problem in Karmic with nvdia-bl-dkms 0.15.2

The install procedure (via synaptic or aptitude) fails when building the module, when searching for : /usr/src/nvidia_bl-0.15.2.dkms.tar.gz

The package seems correctly installed to synaptic though it doesn't work anymore (no OSD slider, no effect on screen backlight).

It seems that it's just a matter of packaging : like the source file has been forgotten at ship time or some stupid reason like this :-)

[Etienne Perot (etienneperot)]

Bug is still here with 0.15.3 (no visible change from 0.15.1, but different from 0.15.2 because it builds)

[Chris Lasher (chris.lasher)]

I am experiencing this bug, both with the 2.6.31-19-generic and 2.6.31-17-generic kernels. I am, however, able to adjust the screen brightness using the F1 and F2 brightness buttons (pushing them without holding down the fn key). The problem however is that the brightness increments or decrements very, very slowly and in tiny amounts. Earlier releases had much larger increment and decrement amounts, and were much more usable. Can we please get back these old values for the brightness increment/decrement?

[Etienne Perot (etienneperot)]

Bug still present in 2.6.31-20-generic (and the alsa backport broke again on that kernel too)

[Νίκος Αλεξανδρής (nikos.alexandris)]

Can't confirm that on my MBP5,1. All works fine.

[Mario Schwalbe (schwalbe)]

Since the F1 and F2 brightness keys and the slider applet also require additional HAL support to work, can someone please confirm whether it works or not by running:

$ cat /sys/class/dmi/id/product_name
$ echo <value between 0 and 1023> | sudo tee /sys/class/backlight/nvidia_backlight/brightness

That's because I got inconsistent reports so far.

[Chris Lasher (chris.lasher)]

$ cat /sys/class/dmi/id/product_name
MacBook5,1
$ echo 0 | sudo tee /sys/class/backlight/nvidia_backlight/brightness[sudo] password for chris:
0

My backlight turned off completely upon entering the second command.

[Etienne Perot (etienneperot)]

$ cat /sys/class/dmi/id/product_name
MacBookPro5,3
$ echo 0 | sudo tee /sys/class/backlight/nvidia_backlight/brightness
[sudo] password for myusernamehere: (typed password)
0 (backlight not changed)
$ echo 512 | sudo tee /sys/class/backlight/nvidia_backlight/brightness
512 (backlight not changed)
$ echo 1023 | sudo tee /sys/class/backlight/nvidia_backlight/brightness
1023 (backlight not changed)
$

I don't know if this is relevant, but back on an older version of Ubuntu, the keys weren't working either and I to work around this I had set up two scripts that I had bound to the F1 and F2 keys, and they basically did the same thing: Incremented or decremented the contents of the brightness pseudo-file. However, the file path was /sys/class/backlight/mbp_backlight/brightness, not /sys/class/backlight/nvidia_backlight/brightness. I do not have a /sys/class/backlight/mbp_backlight/brightness file any more now.

[Mario Schwalbe (schwalbe)]

@WindPower: This isn't relevant, since you installed both drivers nvidia-bl-dkms and mbp-nvidia-bl-dkms. (If you didn't install the latter from the mactel repo, the version provided by the linux kernel should also have been sufficient.) However, until nvidia-bl 0.15.0 nvidia-bl didn't auto-load. mbp-nvidia-bl always does. So, if you added a line to /etc/modules for nvidia-bl, you ended up loading both drivers providing two interfaces in /sys/class/backlight. Furthermore, if the brightness keys didn't work, HAL has just used the wrong interface.

As of nvidia-bl version 0.15.1, I got auto-loading to work. That also means the package now installs a file in /etc/modprobe.d, that blacklists mbp-nvidia-bl. That's why your scripting approach doesn't work anymore - the driver you used is just missing.

Finally, for some strange reason nvidia-bl doesn't work on some MacBook Pro 5 models. Probably those incorporating two graphics adapters. But due to a lack of information, I don't really know.

That means, if you can confirm that nvidia-bl doesn't work (as you did), just deinstall it. There's no reason to have both drivers installed. Unfortunately, mbp-nvidia-bl is also known to not work on some Apple machines. That's why there are both in the repos.

Btw: They aren't completely redundant. While nvidia-bl (in theory) should support a wide range of machine incorporating Nvidia graphics adapters (not just from Apple), does mbp-nvidia-bl only work on Apple machines. In contrast to his name, not just MacBook Pros with Nvidia graphics, but all models incorporating Intel processors.

[Etienne Perot (etienneperot)]

Well, I uninstalled nvidia-bl-dkms, rebooted, and reinstalled mbp-nvidia-bl-dkms, and... surprise, it worked indeed! Thanks, though I guess this bug should still remain open.

[Søren Bredlund Caspersen (soeren-b-c)]

Marking this as invalid in Ubuntu, since it seems like a Mactel issue.

[Pedro Ângelo (pangelo)]

I get:

$ cat /sys/class/dmi/id/product_name
MacBook5,1

$ echo 0 | sudo tee /sys/class/backlight/nvidia_backlight/brightness
0

(nothing happens to backlight)

Removing nvidia-bl-dkms and replacing it by mbp-nvidia-bl-dkms makes the backlight controls work again

This is on a unibody mbp with a dual gpu running ubuntu karmic with the mactel and puredyne ppas

[Νίκος Αλεξανδρής (nikos.alexandris)]

@Pedro Ângelo:

Do you really need the nvidia-bl-dkms if you have a MBP?

[Mihaly Toth (m-toth)]

It works with Macbook 5,1 and Lucid Lynx, but the adjustment is very slow if I install pommed too. Under Karmic everything is OK.