Bug#613747: xserver-xorg-video-radeon: kernel oops observed on init start/shutdown with KMS enabled

[Martin Strauss]

Subject: xserver-xorg-video-radeon: kernel oops on start/shutdown
Package: xserver-xorg-video-radeon
Version: 1:6.13.1-2+squeeze1
Severity: important
Tags: squeeze

Hello,
I installed debian stable squeeze on my laptop lenovo T60 with a Radeon
Mobility X1400 graphic chip.
Unfortunally I observed various kernel oops at boot time (init process) 
and sometimes also at shutdown. The kernel stacktrace seems to arbitrary 
(ie ext4 code, etc).
In seldom cases the screen does switch from console to a black screen 
with some lines on it and then freezes.
If X Server comes up with gdm it seems to run stable.

I installed the linux-firmware-nonfree package which did not help,
Fortunally booting with init=/bin/bash always worked so I was able to 
recover.

After some internet research I disabled KMS in
/etc/modprobe.d/radeon-kms.conf
which made the system rock solid.

After reading the other bug reports I had a look whether linux-firmware-free
was installed and it was missing. So I had another try with KMS enabled 
after installing linux-firmware-free and booted 5 times ... it worked
(Usually it crashed ever second time or so).
I removed linux-firmware-free and rebooted again (with kms) ... no 
crashes ...

So either the system updates of the last to weeks made a difference or
i was just lucky today or having installed linux-firmware-free once is 
just what it needs.

As the default installation produced an unusable installation which only 
an advanced linux user would be able to repair I classified this report 
as Important.

For my self it seems to work (or today is my lucky day).
As I don't trust my luck ...

Is it possible that the missing of linux-firmware-free produces kernel oops?

If interested and if someone can give some advice howto
I could spend the time to do some research ...
currently I have no idea how to reconstruct the effect.

sincerly
Martin Strauss