Re: [PATCH] floppy: revert floppy disable halt warning

From: Alan Cox
Date: Wed Mar 28 2012 - 06:44:09 EST


On Wed, 28 Mar 2012 00:20:46 -0700
"H. Peter Anvin" <hpa@xxxxxxxxx> wrote:

> On 03/27/2012 11:40 PM, Ingo Molnar wrote:
> >
> > No objections from me.
> >
> > Please resubmit against latest -tip, we unified the idle
> > routines which likely interacts with that patch.
> >
>
> To the best of my knowledge, no-hlt only existed because of flaky power
> distributions on 386/486 systems which were sold to run DOS. Since DOS
> did no power management of any kind, including HLT, the power draw was
> fairly uniform; when exposed to the much higher noise levels you got
> when Linux used HLT caused some of these systems to fail.

Also for the Cyrix 5510 which tended to go castors up if a HLT occurred
during a DMA cycle and on a few other boxes HLT during DMA tended to go
astray.

Do we care ? I doubt it. The 5510 was pretty obscure, the 5520 fixed it,
the 5530 is probably the oldest still in any kind of use.

Alan


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/