Re: 2.6.21-rc2 radeon backlight

[David Miller <davem@davemloft.net>]

From: Andrew Morton <akpm@linux-foundation.org>
Date: Fri, 2 Mar 2007 12:29:20 -0800

> On Fri, 02 Mar 2007 09:24:03 -0800
> Alex Romosan <romosan@sycorax.lbl.gov> wrote:
> 
> > Andrew Morton <akpm@linux-foundation.org> writes:
> > 
> > > On Wed, 28 Feb 2007 08:32:43 -0800
> > > Alex Romosan <romosan@sycorax.lbl.gov> wrote:
> > >
> > >> the backlight on my thinkpad still (2.6.20 worked fine) doesn't come
> > >> on if i have the radeon backlight enabled. without it, i guess it's
> > >> the ibm acpi modules that controls the backlight and it seems to work
> > >> fine.
> > >> 
> > >
> > > Unclear. Are you saying that the backlight comes on OK if you use
> > > the IBM acpi module?
> > 
> > yes, if i disable the radeon backlight and use the ibm acpi module,
> > than the backlight works. if i enable the radeon backlight, the screen
> > stays dark and i can't turn it on (i tried using radeontool to control
> > it but nothing happened).
> 
> Richard, is this actually a bug, or is it a config error or something like that?
> 
> And should we track it as a post-2.6.20 regression?

Why don't we compromise for 2.6.21 by marking the Radeon backlight
stuff EXPERIMENTAL until the cases where IBM ACPI works and the
Radeon backlight stuff does not are worked out?