Re: [PATCH] sony-laptop: allow complex per-value input/output validation

[Henrique de Moraes Holschuh <hmh@hmh.eng.br>]

On Tue, 13 Feb 2007, Mattia Dongili wrote:
> On Tue, Feb 13, 2007 at 10:16:59AM -0200, Henrique de Moraes Holschuh wrote:
> > On Tue, 13 Feb 2007, Mattia Dongili wrote:
> > > well this is actually hardware driven, the brightness_default in
> > > sony-laptop only exposes a DSDT method to set this value.
> > > So it's actually one more feature, not a software trick :)
> > > I admit the attribute could be better named 'poweron_brightness'.
> > 
> > ThinkPads can also do this, if we keep their CMOS up-to-date (which we do,
> > currently).  The solution taken by ibm-acpi is to set the power-on
> > brightness at every brighness change, so the machine powers up in the last
> > state it was left in.
> 
> yes, that's the same as in windows. And actually something I did think
> about the same to get rid of the brighness_default stuff, but I'm not
> really convinced it's a nice behaviour, maybe as a configurable option.

It is the least surprise principle at work.  Users can very easily
understand that it will stay at the state they left it.  ThinkPads have been
doing it like that since forever, no matter which the operating system it is
running.

> Anyway, I still believe it could be nice to implement it as a general
> interface in the backlight subsys.

I am not against it, but I don't know if I would take the trouble to
implement that in ibm-acpi.  I'd accept a proper patch doing it, though, if
some thinkpad user ever cared enough to produce one, and the interface
allowed for a default of "don't change".

-- 
  "One disk to rule them all, One disk to find them. One disk to bring
  them all and in the darkness grind them. In the Land of Redmond
  where the shadows lie." -- The Silicon Valley Tarot
  Henrique Holschuh