brightness hotkeys don't work properly in 13.10 on thinkpad x230

[ian]

This is a regression from the behaviour of Kubuntu 13.04, it seems to be caused both by the kernel upgrade and the KDE upgrade. When changing brightness with the laptop function keys, key presses don't correspond to supported brightnesses in the display, and the brightness bar is not displayed.

My laptop is a Thinkpad X230 with an i7-3520M and integrated intel graphics.

On Kubuntu 13.04 with stock packages:
Screen brightness hotkeys work as expected. Increment/decrement in steps of 10, brightness indicator is displayed by KDE.

On Kubuntu 13.04 with KDE 4.11 backport packages from the Kubuntu PPA:
Screen brightness hotkeys still increment/decrement in steps of 10, brightness indicator is not displayed.

On Kubuntu 13.04 with 3.12 mainline kernel from PPA, and stock KDE packages:
Screen brightness keys increment/decrement in steps of 1. Needs 10 button presses for display brightness to change.

On Kubuntu 13.10 daily build *OR* Kubuntu 13.04 with 3.12 mainline kernel and KDE 4.11 backport packages:
Needs 10 button pressses for display brightness to change, no brightness indicator displayed. There also seems to be desync between brightness in the battery monitor applet, and the actual screen brightness.

Expected behaviour:
Same as 13.04 with stock packages.

Please let me know what other info I can provide.

[Ubuntu Foundations Team Bug Bot (crichton)]

Thank you for taking the time to report this bug and helping to make Ubuntu better. It seems that your bug report is not filed about a specific source package though, rather it is just filed against Ubuntu in general. It is important that bug reports be filed about source packages so that people interested in the package can find the bugs about it. You can find some hints about determining what package your bug might be about at https://wiki.ubuntu.com/Bugs/FindRightPackage. You might also ask for help in the #ubuntu-bugs irc channel on Freenode.

To change the source package that this bug is filed about visit https://bugs.launchpad.net/ubuntu/+bug/1230419/+editstatus and add the package name in the text box next to the word Package.

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

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[ian (ian6)]

The brightness indicator bar is still not displayed on KDE 4.11.2 in Saucy.

Adding the following to the kernel boot options in /etc/default/grub fixes the brightness 'steps' part of the issue:

acpi_osi=\"!Windows 2012\"

[madbiologist (me-again)]

This should be fixed in the upstream 3.14-rc4 kernel by these two commits:

commit bd8ba20597f0cfef3ef65c3fd2aa92ab23d4c8e1 - ACPI / video: Filter the _BCL table for duplicate brightness values
commit 0e9f81d3b7cd0649a3bc437391b6a0650f98f844 - ACPI / video: Add systems that should favour native backlight interface

The first one has been cc'd to the stable kernel series. A PPA of the 3.14-rc4 kernel is available at http://kernel.ubuntu.com/~kernel-ppa/mainline/ and instructions on how to install an uninstall it are available at https://wiki.ubuntu.com/Kernel/MainlineBuilds

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[penalvch (penalvch)]

ian, thank you for reporting this bug to Ubuntu. Saucy reached EOL on July 17, 2014.
See this document for currently supported Ubuntu releases: https://wiki.ubuntu.com/Releases

Is this an issue in a supported release? If so, could you please execute the following command, as it will automatically gather debugging information, in a terminal:
apport-collect 1230419

[Launchpad Janitor (janitor)]

[Expired for linux (Ubuntu) because there has been no activity for 60 days.]