Intel, KMS, backlight not going back on after closing the lid

Hi everyone,

I have a very strange thing going on:
laptop: sony vaio z11
linux 2.6.32, 2.6.32.2
Intel Mobile Intel=AE GM45 Express Chipset
Debian/unstable up2date
xserver-xorg-video-intel 2.9.1-1
xserver-xorg 7.4-4
KMS enabled in the kernel config file

The problem is that under special circumstances closing the lid and
reopening it does not turn back on the backlight.

When I do NOT log into any session -> it works (backlight back on)
when I log into a session that does not touch dri/drm -> it works
	(like twm, or lxde)
when I log into a session with dri/drm (composite?) like kde/gnome
	-> backlight remains off after opening the lid and cannot
	   be reactivated again

I tried that several times and it is 100% reproducible.

As soon as I deactivate KMS it works again under all circumstances.

So I assume that it has something to do with the KMS, but I have
no idea how to track that down any further.

Any help is much appreciated.

Best wishes

Norbert
------------------------------------------------------------------------
Norbert Preining            preining@{jaist.ac.jp, logic.at, debian.org}
JAIST, Japan            TU Wien, Austria           Debian TeX Task Force
DSA: 0x09C5B094   fp: 14DF 2E6C 0307 BE6D AD76  A9C0 D2BF 4AA3 09C5 B094
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