On Thu, 31 Mar 2011 07:19:50 -0700 "H. Peter Anvin" <hpa@xxxxxxxxx> wrote: > On 03/31/2011 02:35 AM, Ingo Molnar wrote: > > > > * Alan Cox <alan@xxxxxxxxxxxxxxxxxxx> wrote: > > > >>> Btw., we used to auto-detect broken HLT systems IIRC - but that got lost > >>> already. We should at least honor the boot parameter. > >> > >> I don't believe we ever auto detected them or found a way to do so. That > >> was why the HLT message was printed before hlt was executed. > > > > Yeah - the CPU hang was unrecoverably deep so no auto-detection was possible. > > > > That's seriously ancient stuff - still, keeping the boot option around (<10 > > lines of code) does not hurt anyone. > > > > 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. _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
