Laptop Panel brightness control

[Richard Hughes]

On Mon, 2006-05-22 at 21:14 +0200, Timo Hoenig wrote: 
> On Mon, 2006-05-22 at 17:07 +0100, Richard Hughes wrote:
> 
> > On Fri, 2006-05-12 at 11:01 -0400, David Zeuthen wrote:
> > > Ugh, the joys of borken hardware. 
> 
> Sounds like broken software.

No, this hardware is sending a brightness key event *and* changing it's
own brightness. Usually laptops either do it all in hardware or all in
software. This is just different.

> > According to
> > https://launchpad.net/distros/ubuntu/+source/gnome-power-manager/+bug/44055 we also need to special case the t42.
> 
> As linked from the above URL, I've read the report filed as number
> 340231 on b.g.o.
> 
> Yes, it is true that IBM ThinkPad -- Lenovo ThinkPads, too -- do
> directly control the brightness of the display.  No OS intervention, no
> driver required; user-space could not care less.  Fn-x combination
> pressed, job done.
> 
> Assuming that you're reacting on an event coming through the nvram
> driver:  You should take this as an notification and not as a request
> for action.

Erm... We're getting a:

condition ButtonPressed = brightness-up

from ACPI, which for most laptops means "the buttons been pressed, do
something".

> > Attach patch does so. Please review.
> 
> No, otherwise I -- as outlined above -- it looks like would end up
> blacklisting all ThinkPads in 10-laptop-panel-mgm-policy.fdi.

I don't think it's all the Thinkpads -- I would have had more bugzillas
by now if that were the case.

Richard.