Can't use the lowest brightness setting

Bug #117327 reported by unggnu on 2007-05-28
This bug affects 1 person
Affects Status Importance Assigned to Milestone
In Progress
linux (Ubuntu)
linux-source-2.6.22 (Ubuntu)

Bug Description

Sony TX series and possible many other Sony laptops couldn't use the lowest brightness setting because the default sony_acpi.c restrict the lowest value to one instead of zero. This could save some energy so the difference between Linux and Windows isn't that high any more. I have always patched the sony_acpi.c on my own but since this module isn't integrated in linux.source anymore it is much more harder without recompiling the whole kernel. If there is any Sony laptop which haven't zero as the lowest value it should be no problem since a bug in /etc/acpi/ sets brightness on the lowest option to 33 (which is out of bound 0-8) instead of zero because of spicctrl which seems to have no impact.
Of course the /etc/acpi/ of the acpi-support package have to be patched too.

unggnu (unggnu) wrote :
unggnu (unggnu) wrote :

The spicctrl entry makes no sense for me and results at least on sony_acpi Laptops in a bug (sets brightness on the lowest option to 33 (which is out of bound 0-8)) so I have removed it.

unggnu (unggnu) wrote :

I have made another bug report for acpi-support. If both fixes are accepted I have made another sonybright.patch to fix both problems of /etc/acpi/

unggnu (unggnu) wrote :

Since sony_acpi is deprecated it concerns sony_laptop module which is in the kernel package.

Henrik Nilsen Omma (henrik) wrote :

Thanks for the report and the patch.

Amit, can you have a look?

Changed in linux-source-2.6.22:
assignee: nobody → amitk
importance: Undecided → Low
status: New → Confirmed
unggnu (unggnu) wrote :

Since sony-acpi is deprecated I have made a new patch for sony-laptop.c. It works for me but it might be dirty or erroneous since it isn't as easy as in sony-acpi.c and I have just changed some lines. I have mailed it to the sony-laptop developer so maybe I have some exact information soon.

unggnu (unggnu) wrote :
unggnu (unggnu) wrote :

Since the user space script of acpi-support needs some changes too I have posted another patch. It mainly based on this report so all changes are listed there.
Btw. thanks for supporting this bug report.

unggnu (unggnu) wrote :

Ok, according to sony-laptop developer Mattia Dongili my Patch would break brightness for the other Sony laptops. Since he tries to implement another brightness option I would think that this should be stay backwards unless somebody has working idea.

Colin Watson (cjwatson) wrote :

Moving milestone forward (but from the sound of things maybe this isn't appropriate for 7.10?).

unggnu (unggnu) wrote :

Thanks for your reply. My patch doesn't work with other Sony laptops and if nobody has a working solution I guess we should deferred it to Gutsy+1.
It is not so hard to recompile the module for own needs.
More important for Sony brightness is atm bug #136380.

Hi unggnu,

Care to comment if this is still an issue in the latest Hardy Alpha release? Thanks.

Changed in linux-source-2.6.22:
status: Confirmed → Won't Fix
Changed in linux:
status: New → Incomplete
unggnu (unggnu) wrote :

It is still an issue in current Hardy.

Changed in linux:
assignee: nobody → ubuntu-kernel-team
importance: Undecided → Medium
status: Incomplete → Triaged
Changed in linux:
status: Unknown → Confirmed
Changed in linux:
status: Confirmed → In Progress

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.

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.

Manoj Iyer (manjo) wrote :

Is this still an issue with the latest pre-release of Jaunty 9.04? Refer to . Please let us know.

Changed in linux (Ubuntu):
status: Triaged → Incomplete
unggnu (unggnu) wrote :

This is still an issue in current Jaunty. The upstream report haven't been changed too.

Amit Kucheria (amitk) on 2009-04-28
Changed in linux-source-2.6.22 (Ubuntu):
assignee: Amit Kucheria (amitk) → nobody
milestone: ubuntu-7.10-rc → none
Amit Kucheria (amitk) wrote :

Bug is confirmed in Jaunty/intrepid and Hardy. Upstream bug is still open.

Changed in linux (Ubuntu):
status: Incomplete → Confirmed

[This is an automated message. Apologies if it has reached you inappropriately.]

This bug was flagged as having a patch attached. The Ubuntu Kernel Team's preferred policy is for all patches to be submitted and accepted into the upstream kernel before agreeing to merge them into the Ubuntu kernel. The goal for the Ubuntu kernel is to have little to no divergence from the upstream linux kernel source. has been written to document the suggested policy and procedures for helping get a patch merged upstream and subsequently into the Ubuntu kernel. Please take the time to review that wiki if this patch should be considered for inclusion into the upstream and Ubuntu kernel. Let us know if you have any questions or need any help via the Ubuntu Kernel Team mailing list. Thanks in advance.

tags: added: kj-comment
removed: cft-2.6.27
AceLan Kao (acelankao) wrote :

unggnu, the patch for the file drivers/misc/sony-laptop.c is no longer exist in the current kernel source, so we can't trace the status of upstream bug to know the status.
So, Could you confirm if this is still an issue in karmic?

Changed in linux (Ubuntu):
status: Confirmed → Incomplete
unggnu (unggnu) wrote :

Yes it is still an issue.

unggnu (unggnu) on 2010-03-16
Changed in linux (Ubuntu):
status: Incomplete → Confirmed
Andy Whitcroft (apw) wrote :

Dropped the 'is a patch for this issue' off of the patches as they no longer could fix the issue per comment #21. Could we also confirm that the issue still exists in Natty. Please report back here.

Changed in linux:
importance: Unknown → Low

unggnu, 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? If so, could you please test for this with the latest development release of Ubuntu? ISO images are available from .

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

apport-collect -p linux <replace-with-bug-number>

Also, could you please test the latest upstream kernel available following ? It will allow additional upstream developers to examine the issue. Please do not test the daily folder, but the one all the way at the bottom. Once you've tested the upstream kernel, please comment on which kernel version specifically you tested. If this bug is fixed in the mainline kernel, please add the following tags:

where VERSION-NUMBER is the version number of the kernel you tested. For example:

This can be done by clicking on the yellow circle with a black pencil icon next to the word Tags located at the bottom of the bug description. As well, please remove the tag:

If the mainline kernel does not fix this bug, please add the following tags:

As well, please remove the tag:

If you are unable to test the mainline kernel, please comment as to why specifically you were unable to test it and add the following tags:

Once testing of the upstream kernel is complete, please mark this bug's Status as Confirmed. Please let us know your results. Thank you for your understanding.

tags: added: needs-kernel-logs needs-upstream-testing
Changed in linux (Ubuntu):
status: Confirmed → Incomplete
summary: - Sony TX series and possible many other Sony laptops couldn't use the
- lowest brightness setting
+ Can't use the lowest brightness setting
Changed in linux (Ubuntu):
assignee: nobody → Chintana Prabhu (chintanarp98)
Changed in linux (Ubuntu):
status: Incomplete → In Progress

Chintana Prabhu, please _stop_ changing the Status, or marking yourself assigned. For more on this, please see .

Changed in linux (Ubuntu):
assignee: Chintana Prabhu (chintanarp98) → nobody
status: In Progress → Incomplete
To post a comment you must log in.
This report contains Public information  Edit
Everyone can see this information.

Other bug subscribers

Related questions

Remote bug watches

Bug watches keep track of this bug in other bug trackers.