Screen Brightness Little Pop-up window does not show the correct Brightness on Thinkpads X60, T60p, Z60t

Bug #71204 reported by Littleiffel on 2006-11-10
Affects Status Importance Assigned to Milestone
linux (Ubuntu)
linux-source-2.6.20 (Ubuntu)

Bug Description

If i want to change the brightness of my screen on a Thinkpad x60 in Ubuntu 6.10 (Edgy Eft), a small pop up window displays. However, I am able to adjust screen brightness with the hardware buttons(FN+home/FN+End), however the small pop up either displays half-full when on battery an full when on AC-Adapter.

Well everything is working, it is just since this pop-up is new it would be impressive if it was displaying the screen brightness level correctly

Andrew Ash (ash211) wrote :

Thanks for the bug report. Did this popup not appear in previous versions of Ubuntu? Does it work correctly in other distributions of linux?

Littleiffel (thierry-nicola) wrote :

I haven't seen this popup so far. So I am sure it was not there(or not working) in Dapper, on the same machine.

I haven't used others distros on this machine, but if I find time for testing I will try with some LiveCds.

Andrew Ash (ash211) wrote :

Let me see if I've got this straight. Adjusting screen brightness with the hardware buttons changes the brightness of the screen. It also triggers a window to appear that displays the brightness level. The problem is that no matter what the actual brightness of the screen, the popup stays on half-full with battery and full when on AC adapter.

Is that correct?

Littleiffel (thierry-nicola) wrote :

Yes that is correct.

Andrew Ash (ash211) wrote :

Great. Now we just need to figure out what package is responsible for drawing this window.

chastell (chastell) wrote :

FWIW, hotkey-setup seems to be responsible for drawing the volume popup (see #88029), so might be responsible for this popup as well.

I have this problem too. The brightness as reported in /proc/acpi/ibm/brightness is probably where the on-screen-display is getting the value, but for some reason this is not reporting the "true" brightness of the screen. I believe that adding the experimental=1 argument when loading the ibm-acpi module may correct the issue.

See for more info.

I have this working in gentoo with the tpb daemon.

DaveAbrahams (boostpro) wrote :

Having exactly the same problem in Feisty on my T60p. I rebooted in my old Edgy installation and was surprised to find out that it was worse there. The bar shows about 70% on AC and the brightness keys don't change the brightness.

Note that in both Edgy and feisty, /etc/modprobe.d/ibm_acpi.modprobe contains

  options ibm_acpi hotkey=enable,0xff9f experimental=1

Guillaume Duveau (guix) wrote :

Exactly the same on my Z60t with Feisty, 2.6.20-16-generic

Guillaume Duveau (guix) wrote :

Since /proc/acpi/ibm/brightness keeps the same value for "level" despite the changes, this should be a kernel bug rather than a hal bug.

Guillaume Duveau (guix) wrote :

/proc/acpi/ibm/brightness keeps the same value, so it's a kernel bug

Changed in hal:
status: Unconfirmed → Rejected

I have noticed that the permissions in /proc/acpi/ibm/ are read only for everyone except root. Some of the files in here can be directly manipulated to cause changes in fan speed, brightness, volume level, etc.; however, you must be root (or have a process with the right permission) to do it. Perhaps finding out why these are all read-only could point to the source of the problem?

Martin Man (mman) wrote :

I see the same bug on T41p. I'm sure this was working fine on Feisty and stopped working the first day dist-upgraded to gutsy (around tribe2).

Ugo Riboni (uriboni) wrote :

This happens also on a Thinkpad R61, with Gutsy final release.

Additionally, writing to the proc node with commands like
echo level 7 > /proc/acpi/ibm/brightness
changes the value reported by the node, but it doesn't change the actual brightness.

The Fn+key combinations to change brightness work, but only when accessing a console via CTRL+ALT+Fn
See also bug #137972

Guillaume Duveau (guix) wrote :

Update on my Z60t I migrated from Feisty to Gutsy I don't have any pop-up at all. I prefer it like this, nothing is better than something wrong for a gadget thing like that but it's strange nonetheless !

Beginning with the Hardy Heron 8.04 development cycle, all open Ubuntu kernel bugs need to be reported against the "linux" kernel package. We are automatically migrating this bug to the new "linux" package. However, development has already began for the upcoming Intrepid Ibex 8.10 release. It would be helpful if you could test the upcoming release and verify if this is still an issue - . If the issue still exists, please update this report by changing the Status of the "linux" task from "Incomplete" to "New". We appreciate your patience and understanding as we make this transition. Thanks!

The Ubuntu Kernel Team is planning to move to the 2.6.27 kernel for the upcoming Intrepid Ibex 8.10 release. As a result, the kernel team would appreciate it if you could please test this newer 2.6.27 Ubuntu kernel. There are one of two ways you should be able to test:

1) If you are comfortable installing packages on your own, the linux-image-2.6.27-* package is currently available for you to install and test.


2) The upcoming Alpha5 for Intrepid Ibex 8.10 will contain this newer 2.6.27 Ubuntu kernel. Alpha5 is set to be released Thursday Sept 4. Please watch for Alpha5 to be announced. You should then be able to test via a LiveCD.

Please let us know immediately if this newer 2.6.27 kernel resolves the bug reported here or if the issue remains. More importantly, please open a new bug report for each new bug/regression introduced by the 2.6.27 kernel and tag the bug report with 'linux-2.6.27'. Also, please specifically note if the issue does or does not appear in the 2.6.26 kernel. Thanks again, we really appreicate your help and feedback.

Markus Korn (thekorn) wrote :

Unfortunately this bug report is being closed because we received no response to the last inquiry for information. However, the Intrepid Ibex 8.10 Beta release was most recently announced - . If you are able to confirm this is still an issue with this most recent release please feel free to reopen this report. To reopen the bug report you can click on the current status, under the Status column, and change the Status back to "New".


Changed in linux:
status: Incomplete → Won't Fix

Per a decision made by the Ubuntu Kernel Team, bugs will longer be assigned to the ubuntu-kernel-team in Launchpad as part of the bug triage process. The ubuntu-kernel-team is being unassigned from this bug report. Refer to for more information. Thanks.

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