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#1 2014-06-29 00:50:10

ben.pote
Member
Registered: 2014-02-14
Posts: 6

Thinkpad T430 backlight control

I'm having some issues with the backlight controls on my laptop. Weirdly the other f-key alternate functions (sleep, wireless off, etc) are working, but I discovered last night when using the computer in a dark room that my brightness controls weren't working anymore (in other words, I'm not sure for how long they've been broken or what update might have broken them).

I have the following relevant output in dmesg:

725:[    7.339394] thinkpad_acpi: ThinkPad ACPI Extras v0.25
726:[    7.339395] thinkpad_acpi: http://ibm-acpi.sf.net/
727:[    7.339395] thinkpad_acpi: ThinkPad BIOS G1ET73WW (2.09 ), EC unknown
728:[    7.339396] thinkpad_acpi: Lenovo ThinkPad T430, model 2349S7W
729:[    7.339808] thinkpad_acpi: Unsupported brightness interface, please contact ibm-acpi-devel@lists.sourceforge.net
730:[    7.339907] thinkpad_acpi: radio switch found; radios are enabled
731:[    7.339985] thinkpad_acpi: This ThinkPad has standard ACPI backlight brightness control, supported by the ACPI video driver
732:[    7.339986] thinkpad_acpi: Disabling thinkpad-acpi brightness events by default...
733:[    7.341034] thinkpad_acpi: Console audio control enabled, mode: monitor (read only)
734:[    7.342254] input: ThinkPad Extra Buttons as /devices/platform/thinkpa _acpi/input/input7
838:[ 4343.989875] thinkpad_acpi: EC reports that Thermal Table has changed
840:[37051.969894] thinkpad_acpi: EC reports that Thermal Table has changed

and when I do acpi_listen I see the following when hitting the brightness keys:

video/brightnessdown BRTDN 00000087 00000000
video/brightnessup BRTUP 00000086 00000000

Anyone have an idea of what's going on, or how I can fix the 'Unsupported brightness interface' error? I searched the archives for the ibm-acpi-devel list but didn't find anything helpful.

Edit: I'm running i3, and my laptop has the Intel video card and 1600x900 screen.

Last edited by ben.pote (2014-06-29 00:55:04)

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#2 2014-06-29 03:24:33

ben.pote
Member
Registered: 2014-02-14
Posts: 6

Re: Thinkpad T430 backlight control

For anyone finding this via search, the solution that restored backlight adjusting capability was to add the following kernel parameter:

acpi_osi="!Windows 2012"

from this bug report. I also tried

video.use_native_backlight=1

but had no success with that one.

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#3 2014-06-29 05:16:47

WonderWoofy
Member
From: Los Gatos, CA
Registered: 2012-05-19
Posts: 8,412

Re: Thinkpad T430 backlight control

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