Messages in this thread | | | Date | Thu, 31 Mar 2011 08:09:12 -0700 | From | "H. Peter Anvin" <> | Subject | Re: [PATCH 2/9] x86 idle: remove NOP cpuinfo_x86.hlt_works_ok flag |
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On 03/31/2011 07:41 AM, Alan Cox wrote: >> >> What it was was bad power supplies or low-capacitance, high-inductance >> power distribution that happened to work with MS-DOS which always burned >> the CPU at 100% and therefore left the power draw relatively consistent >> current. A proper OS putting the CPU in HLT produced a lot more high >> frequency noise on the power busses, with disastrous results without >> proper bypass. > > And also chipset errata in some cases - eg some revisions of the CS5510 > hung the box solid if a CPU hlt occurred during an IDE transfer. I don't > think any CS5510s are still around although I've had mail from someone > with a CS5520 in use not that long ago so who knows! > > The joy of ancient history.
Ah, yes, I guess there was a special cycle on the bus which the chipset could misinterpret.
-hpa
-- H. Peter Anvin, Intel Open Source Technology Center I work for Intel. I don't speak on their behalf.
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