Re: [intel/acpi] backlight

[Len Brown <lenb@kernel.org>]

On Mon, 1 Dec 2008, Zhao Yakui wrote:

> On Fri, 2008-11-28 at 14:47 +0800, Yves-Alexis Perez wrote:
> > Hi,
> > 
> > I'm running linux 2.6.28-rc6-00007-ged31348 on my Thinkpad T61, with
> > Intel GM965. Under X, brightness keys work fine most of the time, but in
> > some case it fails (for example after a dpms force off, but not always).
> > Switching to console and back to X fix the problem for a time.

> Will you please confirm whether the issue still exists if DPMS is not
> used?

I don't have DPMS enabled, and if editing xorg.conf is required
to enable it, I never will.
	
> > Another weird stuff is that, in single user, I have no way to control
> > the backlight. Using brightness key doesn't work,
> > and /sys/class/backlight/acpi_video0 doesn't do anything.

> Can you confirm whether the i915 driver is loaded in single user mode?
> If not, please load it and see whether the interface
> of /sys/class/backlight/* can work.

In 2.6.28...

in single user mode, i915 is not loaded,
/sys/class/backlight/acpi_video0 does NOT work

modprobe of i915 does not change this.

In 2.6.27

in single user mode, i915 is not loaded,
/sys/class/backlight/acpi_video0 does NOT work
/sys/class/backlight/acpi_video1 DOES work

modprobe of i915 does not change this.

-Len