xf86-video-intel

[Peter Clifton]

On Tue, 2007-11-20 at 23:05 +0000, Colin Guthrie wrote:
> Sergio Monteiro Basto wrote:
> > On Tue, 2007-11-20 at 21:39 +0100, Lukas Hejtmanek wrote:
> >> Hello,
> >>
> >> I noticed that you did some improvements to the backlight support in the video
> >> driver. Would it be possible to add an option "do not touch backlight"?
> >>
> >> Currently, I use backlight level 0 and I highly dislike that starting the
> >> X server or playing a movie in mplayer rises backlight to level 7. I do not
> >> want it.
> >>
> > 
> > backlight support, is the lid button ?
> 
> No backlight is the light behind the lcd. It /should/ (arguable) be
> turned off when the lid is closed (as there is little point it in being
> on!!), but this is probably something that should be controlled by
> something higher up the stack than the driver (please correct me if I'm
> wrong). I say this more out of principle rather than practicality as I
> cannot think of *any* reason why the backlight should remain on with the
> lid closed (and thus there is nothing wrong with this being in the
> driver), but the whole backlight control (dim level) when on power vs
> battery and what to do when the lid is closed (suspend, nowt, depend on
> power status etc.) are probably all handled by the same system e.g.
> gnome-power-manager or equiv (again please correct me if I'm wrong here
> and this is a pure HAL thing....)

AFAIK, the Xorg driver asks the BIOS not to do the backlight turn on /
off with the lid switch, so the BIOS doesn't change brightness registers
behind the driver's back.

The driver should ensure some safety measure is in place to switch the
back-light off when the lid is shut, as not doing so results in
overheated laptops.

Best wishes,

-- 
Peter Clifton

Electrical Engineering Division,
Engineering Department,
University of Cambridge,
9, JJ Thomson Avenue,
Cambridge
CB3 0FA

Tel: +44 (0)7729 980173 - (No signal in the lab!)