Re: p4-clockmod not working in 2.6.16

From: Mike Galbraith
Date: Wed Mar 22 2006 - 01:17:40 EST

On Wed, 2006-03-22 at 06:57 +0100, Edgar Toernig wrote:

> And at last: reading Intel's errata it should be good enough to not go
> below 25% instead limiting all below 2GHz. I'm not even sure whether
> the 2GHz mentioned there is the reduced or the nominal clock. Running
> 2GHz on 12.5% would be a really fast CPU.
> | N60. Processor May Hang under Certain Frequencies and 12.5%
> | STPCLK# Duty Cycle
> |
> | Problem: If a system de-asserts STPCLK# at a 12.5% duty cycle, the
> | processor is running below 2 GHz, and the processor thermal
> | control circuit (TCC) on-demand clock modulation is active,
> | the processor may hang. This erratum does not occur under
> | the automatic mode of the TCC.
> |
> | Implication: When this erratum occurs, the processor will hang.
> |
> | Workaround: If use of the on-demand mode of the processor's TCC is desired
> | in conjunction with STPCLK# modulation, then assure that STPCLK#
> | is not asserted at a 12.5% duty cycle.

Yeah, I read that too, and it looked to me like someone might have used
a bit too mich blunt force. (not sure though) I disabled it so I could
save a tree or two, and it seems to work fine. Of course, if it does
ever have a seizure, I don't get to gripe ;-)


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