Re: hpet_disable() call sites

From: Thomas Gleixner
Date: Tue Mar 27 2012 - 08:59:14 EST


On Tue, 27 Mar 2012, Jan Beulich wrote:
> up kernel has a problem if the HPET is in an unexpected state, in
> particular preventing "normal" timer interrupts from occurring (which
> was in particular found to be the case during kdump attempts after
> Xen was running).

What's Xen doing special with the hpet ?

> Is there any reason why hpet_disable() should not also be called
> from (or some equivalent action be taken, perhaps including clearing
> certain bits in the individual counters' configuration registers, which
> are apparently - but perhaps wrongly - implied to be clear in e.g.
> hpet_set_mode(), in) hpet_enable()?

No, there is no particular reason why we don't clear those registers.

Thanks,

tglx
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