Illuminated keyboard on ASUS U50VG laptop, backlight or led ?

[Corentin Chary]

On Thu, Aug 6, 2009 at 12:48 PM, Danny Kukawka<danny.kukawka at web.de> wrote:
> On Donnerstag, 6. August 2009, Corentin Chary wrote:
>> Hi Danny,
>> I was trying to add keyboard_backlight.num_levels support for your modified
>> led-addon. But there is something I don't understand :-
>> keyboard_backlight.num_levels is used in:
>> - examples/light_sensors_and_keyboard_backlight.py
>> - fdi/policy/10osvendor/10-macbookpro-utils.fdi
>> - kde/solid/hal/halpower.cpp
>> But it is not defined in doc/spec/hal-spec-properties.xml.
>>
>> Should I make another patch to fix hal-spec-properties ?
>
> Can you please provide a "grep . */*" from /sys/class/leds/ with the affected
> device? If I read the kernel doc for leds (which this device is), we don't
> need a num_levels for it:
>
> http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=blob;f=Documentation/leds-class.txt;h=6399557cdab3d6542a0feea0c0cd2c6b2af5ffad;hb=HEAD
>
> "... The brightness file will set the brightness of the LED (taking a value
> 0-255). Most LEDs don't have hardware brightness support so will just be
> turned on for non-zero brightness settings. ..."
>

The documentation is probably out of date, the led class provide
a max_brightness file. 255 is the default value, but it can be overridden.

See: http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=blob;f=drivers/leds/led-class.c;h=f2cc13d76810f457c752d6f92f53759980f465ea;hb=HEAD#l76

leds-dac124s085.c define it to 0xFFF for example.
And asus-laptop will soon use 3 as max_brightness for asus::kbd_backlight.

But still, it seems that examples/light_sensors_and_keyboard_backlight.py
and others are using something that is not defined in hal-spec-properties.

Thanks,
-- 
Corentin Chary
http://xf.iksaif.net - http://uffs.org