Re: [3/3] 2.6.21-rc7: known regressions (v2)

["Antonino A. Daplas" <adaplas@gmail.com>]

On Wed, 2007-04-25 at 09:01 -0400, Dave Jones wrote:
> On Wed, Apr 25, 2007 at 01:31:02PM +0200, Adrian Bunk wrote:
>  > On Wed, Apr 25, 2007 at 04:06:05AM -0700, Andrew Morton wrote:
>  > > On Mon, 23 Apr 2007 23:49:09 +0200 Adrian Bunk <bunk@stusta.de> wrote:
>  > >...
>  > > > Subject    : ThinkPad X60: resume no longer works  (PCI related?)
>  > > >              workaround: CONFIG_FB_BACKLIGHT=n
>  > > > References : http://lkml.org/lkml/2007/3/13/3
>  > > > Submitter  : Dave Jones <davej@redhat.com>
>  > > > Caused-By  : PCI merge
>  > > >              commit 78149df6d565c36675463352d0bfe0000b02b7a7
>  > > > Handled-By : Eric W. Biederman <ebiederm@xmission.com>
>  > > >              Rafael J. Wysocki <rjw@sisk.pl>
>  > > >              Antonino A. Daplas <adaplas@gmail.com>
>  > > > Status     : unknown
>  > > 
>  > > Is this related to the problems Jeremy has been looking at?
>  > >...
>  > 
>  > Dave and Jeremy hran into similar looking but most likely different 
>  > problems.
>  > 
>  > For Jeremy -rc7 is working fine, but for Dave it doesn't.
> 
> I think this was due to Jeremy not having CONFIG_FB_BACKLIGHT=y in his config.

This is really weird, as CONFIG_FB_BACKLIGHT just selects
BACKLIGHT_CLASS and LCD_CLASS, and adds an entry (bl_curve)
under /sys/class/backlight/*/. ACPI_IBM which is set (presumably) in
Dave's kconfig, also selects the BACKLIGHT_CLASS. And the only possible
framebuffer drivers in the thinkpad are vesafb and intelfb, none of
which has a backlight driver.

I'm still at a loss how this happens.  Dave, can you post your config?
And have you tried the following settings:

FB_BACKLIGHT=y
ACPI_IBM=n
ACPI_VIDEO=n

I'm also adding Richard Purdie to the CC list.

Tony 

PS: I also get a blank display on resume with a Toshiba laptop.  But
cycling through the Fn keys brings it back.  I don't know if this is a
regression, I will have to try older kernels.