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

From: Pavel Machek
Date: Wed Jan 13 2016 - 14:10:37 EST


On Wed 2016-01-13 20:07:36, Pavel Machek wrote:
> On Wed 2016-01-13 09:54:55, Pali Rohár wrote:
> > On Tuesday 12 January 2016 22:58:04 Pavel Machek wrote:
> > > Hi!
> > >

> > > Next question is.. apparently there are some keyboards that have
> > > per-key RGB backlight... but maybe we can just call that "weird
> > > enough" and ignore...
> >
> > First we need to defines stable kernel ABI for keyboard backlight. And I
> > suggest to use existing convention used by upower/console-kit and other
> > userspace apps...
>
> Hmm... I'm not sure that can be done. What were the masks used by
> upower again? Will upower write to all 6 leds if we present them?

Got it...

It has function up_kbd_backlight_find() which do:

/* find a led device that is a keyboard device */
while ((filename = g_dir_read_name (dir)) != NULL) {
if (g_strstr_len (filename, -1, "kbd_backlight") != NULL) {
dir_path = g_build_filename ("/sys/class/leds",
filename,
NULL);
break;

That suggests that it stops at the first matching device. Adding new
"virtual" led controlling 6 physical leds would be ugly. So... new
interface should be done.

Pavel
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html