FN Brightness keys stopped working on Macbook4,1

[spaetz]

This is a spin-off of bug 406515, which was hijacked to be about Lenovo-only. So this one is about Macbooks.
In Karmic the FN Brightness keys don't work in KMS mode; all other fn keys still function as intended.

If I disable KMS via boot parameter "nomodeset", the fn keys work again. I do not have any files in /sys/class/backlight. Other debug output was reported in bug 406515, let me know if I can give you more information. This has been occuring since at least early Karmic alphas until now (2.6.31-18-generic).

ProblemType: Bug
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC1: spaetz 2300 F.... pulseaudio
 /dev/snd/controlC0: spaetz 2300 F.... pulseaudio
CRDA: Error: command ['iw', 'reg', 'get'] failed with exit code 1: nl80211 not found.
Card0.Amixer.info:
 Card hw:0 'Intel'/'HDA Intel at 0x90700000 irq 20'
   Mixer name : 'Realtek ALC889A'
   Components : 'HDA:10ec0885,106b3600,00100103'
   Controls : 34
   Simple ctrls : 21
Card1.Amixer.info:
 Card hw:1 'Headset'/'Logitech Logitech USB Headset at usb-0000:00:1a.7-2.1, full speed'
   Mixer name : 'USB Mixer'
   Components : 'USB046d:0a02'
   Controls : 6
   Simple ctrls : 2
Date: Tue Jan 19 09:09:38 2010
DistroRelease: Ubuntu 9.10
HibernationDevice: RESUME=UUID=c7ce724c-7bdc-4df0-9ee0-d8cef3f3085a
MachineType: Apple Inc. MacBook4,1
NonfreeKernelModules: wl
Package: linux-image (not installed)
ProcCmdLine: BOOT_IMAGE=/boot/vmlinuz-2.6.31-18-generic root=UUID=76b84d27-4b58-4836-bfea-68506d396d51 ro quiet splash ipv6.disable=1 acpi_backlight=vendor
ProcEnviron:
 SHELL=/bin/bash
 PATH=(custom, user)
 LANG=C
ProcVersionSignature: Ubuntu 2.6.31-18.55-generic
RelatedPackageVersions:
 linux-backports-modules-2.6.31-18-generic N/A
 linux-firmware 1.26
RfKill:
 2: hci0: Bluetooth
  Soft blocked: no
  Hard blocked: no
SourcePackage: linux-meta
Uname: Linux 2.6.31-18-generic x86_64
WpaSupplicantLog:

dmi.bios.date: 02/09/08
dmi.bios.vendor: Apple Inc.
dmi.bios.version: MB41.88Z.00C1.B00.0802091535
dmi.board.asset.tag: Base Board Asset Tag
dmi.board.name: Mac-F22788A9
dmi.board.vendor: Apple Inc.
dmi.board.version: PVT
dmi.chassis.asset.tag: Asset Tag#
dmi.chassis.type: 2
dmi.chassis.vendor: Apple Inc.
dmi.chassis.version: Mac-F22788A9
dmi.modalias: dmi:bvnAppleInc.:bvrMB41.88Z.00C1.B00.0802091535:bd02/09/08:svnAppleInc.:pnMacBook4,1:pvr1.0:rvnAppleInc.:rnMac-F22788A9:rvrPVT:cvnAppleInc.:ct2:cvrMac-F22788A9:
dmi.product.name: MacBook4,1
dmi.product.version: 1.0
dmi.sys.vendor: Apple Inc.

[spaetz (spaetz)]

The fix proposed in the other bug (kernel parameter acpi_backlight=vendor) does not fix things on the MacBook4,1 by the way. Just one more datapoint (as as the attached apport data is showing that as my current kernel parameter :-))

[David Tombs (dgtombs)]

Just to clarify, this worked in Jaunty but stopped working in Karmic, correct?

[spaetz (spaetz)]

Yes, exactly. Brightness keys worked like a charm in Jaunty (which is not surprising as it did not use KMS). As I set, I can "fix" this by disabling KMS.

[Colin D Bennett (colinb)]

Is it the keys that specifically are not working, or is it more properly the backlight adjustment that is not working? That is, when you hit the backlight +/- Fn keys, does Ubuntu respond by showing the notification bubble indicating the brightness level with a bar by the system tray, or do the Fn keys simply not produce any response at all?

My LCD backlight brightness adjustment stopped working in Karmic after some package update. The Fn keys still work for me, as in Ubuntu sees the key press events and tries to change the display backlight brightness, but the LCD backlight doesn't change brightness. Writing to /sys/class/backlight/nvidia_backlight/brightness also produces no change.

[spaetz (spaetz)]

@Colin, neither the keys work (no brightness changes), nor do you get any notification bubble.

The Macbook has no ACPI backlight driver and /sys/class/backlight is empty.

This has an upstream bug now at https://bugs.freedesktop.org/show_bug.cgi?id=25901
A patch has been posted there but not gone into any upstream.

[Jeremy Foshee (jeremyfoshee)]

Hi spaetz,

This bug was reported a while ago and there hasn't been any activity in it recently. We were wondering if this is still an issue? Can you try with the latest development release of Ubuntu? ISO CD images are available from http://cdimage.ubuntu.com/releases/ .

If it remains an issue, could you run the following command from a Terminal (Applications->Accessories->Terminal). It will automatically gather and attach updated debug information to this report.

apport-collect -p linux 509508

Also, if you could test the latest upstream kernel available that would be great. It will allow additional upstream developers to examine the issue. Refer to https://wiki.ubuntu.com/KernelMainlineBuilds . Once you've tested the upstream kernel, please remove the 'needs-upstream-testing' tag. This can be done by clicking on the yellow pencil icon next to the tag located at the bottom of the bug description and deleting the 'needs-upstream-testing' text. Please let us know your results.

Thanks in advance.

    [This is an automated message. Apologies if it has reached you inappropriately; please just reply to this message indicating so.]

[spaetz (spaetz)]

This is fixed now for the Macbook 4,1 in Lucid.