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From: Alan Cox <alan@lxorguk.ukuu.org.uk>
To: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@kernel.org>, Josh Boyer <jwboyer@gmail.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Stephen Hemminger <shemminger@vyatta.com>,
	Len Brown <len.brown@intel.com>,
	linux-kernel@vger.kernel.org, Ingo Molnar <mingo@elte.hu>
Subject: Re: [PATCH] floppy: revert floppy disable halt warning
Date: Wed, 28 Mar 2012 11:46:27 +0100	[thread overview]
Message-ID: <20120328114627.51b64541@pyramind.ukuu.org.uk> (raw)
In-Reply-To: <4F72BBCE.1060307@zytor.com>

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



      parent reply	other threads:[~2012-03-28 10:44 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-03-11 16:38 [PATCH] floppy: revert floppy disable halt warning Stephen Hemminger
2012-03-27 23:26 ` Andrew Morton
2012-03-28  0:24   ` Josh Boyer
2012-03-28  6:40     ` Ingo Molnar
2012-03-28  7:20       ` H. Peter Anvin
2012-03-28  7:34         ` Ingo Molnar
2012-03-28 10:46         ` Alan Cox [this message]

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