Re: [PATCH] thinkpad_acpi: Add support for keyboard backlight

From: Johannes Stezenbach
Date: Mon Jan 11 2016 - 16:12:49 EST

On Mon, Jan 11, 2016 at 09:03:01PM +0100, Pali Rohár wrote:
> On Monday 11 January 2016 20:28:00 Henrique de Moraes Holschuh wrote
> > The two features are not the same (and are handled differently by the
> > firmware, for whatever reason), although they do serve the same
> > purpose. I don't think a thinkpad will ever have both features at
> > the same time, so I have no idea why they changed the firmware
> > interface.
> And more important, I was told that ThinkPad x230 comes in variant with
> both ThinkLight (that LED upper the display) and keyboard backlight
> (under they keyboard).

I can confirm this, my x230 has both. FWIW, BIOS hotkey
Fn+Space cycles through off, dim backlight, full backlight
and full thinklight. /sys/class/leds/tpacpi::thinklight/brightness
can be read (showing either 0 or 255) but writes are ignored.
Dito for /proc/acpi/ibm/light.