[ltp] apm and preemptive kernel patch

Tino Keitel linux-thinkpad@www.bm-soft.com
Mon, 5 Aug 2002 09:59:46 +0200


On Sun, Aug 04, 2002 at 22:44:38 +0200, Thomas Hood wrote:
> The apm driver in the kernel is not SMP safe.
> I would conclude, therefore, that it is not preempt
> safe either.
> 
> Please correct me if I'm wrong.

Somebody told me that the APM driver of the kernel is not preempt safe
because it misses some locks that are required. The preempt patch will
make it possible to intercept the APM routines and access APM
resources that should be protected by locks. The same problem applies
to a SMP enabled kernel (kernel threads). The same guy told me that a
patch called low latency patch could work without breaking APM.

Please correct me if I'm wrong. :-)

-- 
tino.keitel@innominate.com
dipl.-inf.                        Innominate Security Technologies AG
software engineer                                   networking people
tel: +49.30.6392-3308                      http://www.innominate.com/

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