laptop-mode causing kernel hangs in Hoary?

[Justin Mason]

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hi folks --

I think I may have figured out something that was causing total system
hangs for me in Hoary.

The machine works great on AC, but once it was on battery for a short
amount of time (varying between 20 seconds and ~15 minutes) it would
suddenly hang hard.   Nothing would get it going, short of a power cycle.
(I didn't get a chance to try the magic-sysrq key though.)  There was no
message issued at that time in the syslog.

It now appears that the problem was laptop-mode -- by default, as far as I
can see, Hoary installs laptop_mode and runs it from init.d on boot; once
I turned that off, I haven't yet had a hang.

I'm running a vanilla 2.6.10 kernel with madwifi and vmware; not the
Ubuntu vendor kernel.  I'm also using APM, not ACPI.  Hardware is an IBM
Thinkpad T40.

Has anyone run into this before?  It seems entirely new, nothing on
google along those lines...

- --j.
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