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

[Darren Hart]

On Sat, Jan 09, 2016 at 03:46:41PM -0200, Henrique de Moraes Holschuh wrote:
> On Sat, Jan 9, 2016, at 15:39, Henrique de Moraes Holschuh wrote:
> > On Mon, Jan 4, 2016, at 18:12, Pavel Machek wrote:
> > > > This patch adds support for controlling keyboard backlight via standard
> > > > linux led class interface (::kbd_backlight). It uses ACPI HKEY device with
> > > > MLCG and MLCS methods.
> > > > 
> > > > Signed-off-by: Pali Rohár <pali.rohar@xxxxxxxxx>
> > > > Tested-by: Fabio D'Urso <fabiodurso@xxxxxxxxxx>
> > > 
> > > On my thinkpad, keyboard light is controlled by
> > > 
> > > /sys/class/leds/tpacpi\:\:thinklight/brightness
> > > 
> > > (that's a bad name).
> > 
> > That's because the driver was not updated to support your laptop, AND I
> > don't recall if someone mapped the full behavior of the ACPI thinklight
> > interface in your thinkpad :-(
> 
> Argh.  If by "keyboard light" you mean the LED above the *screen* that
> shines down on the whole keyboard, please disregard my previous reply...
> 
> As for the naming, the idea of a LED up there shining in the keyboard
> is:
>  1. patented by IBM
>  2. named "ThinkLight" by IBM, one of the "Think Technologies" in the
>  "ThinkPad" (add TM after everything :p)  and every
>      old-timer thinkpad user knew it by that name.
>  4. called "thinklight" by the driver since before the LED sysfs class
>  even existed :p
> 
> ibm-acpi, since then renamed thinkpad-acpi *predates* most generic
> interfaces.  Heck, it predates sysfs.
> 
> So, this is ABI set in stone.  If there is a way to add an "alias" of
> kbd_backlight that won't drive userspace crazy, we might do that though.
>  But it looks quite risky to me...

Henrique, so are you taking back your Ack from 10 minutes prior?

I've dropped this patch. Please let me know if I should pick it back up.

-- 
Darren Hart
Intel Open Source Technology Center