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From: Alain Knaff <alain@knaff.lu>
To: Andi Kleen <andi@firstfloor.org>
Cc: Arjan van de Ven <arjan@infradead.org>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Mark Hounschell <markh@compro.net>,
	"Pallipadi, Venkatesh" <venkatesh.pallipadi@intel.com>,
	"dmarkh@cfl.rr.com" <dmarkh@cfl.rr.com>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	"fdutils@fdutils.linux.lu" <fdutils@fdutils.linux.lu>,
	"Li, Shaohua" <shaohua.li@intel.com>, Ingo Molnar <mingo@elte.hu>,
	morgan@physics.ucla.edu
Subject: Re: [Fdutils] DMA cache consistency bug introduced in 2.6.28
Date: Mon, 28 Dec 2009 11:27:56 +0100	[thread overview]
Message-ID: <4B38882C.7060903@knaff.lu> (raw)
In-Reply-To: <20091228015446.GA3012@basil.fritz.box>

Andi Kleen wrote:
>> disable_hlt/enable_hlt was only needed to work around a bug on TM4000
>> (Texas Instrument) Laptops which were popular around 1994 / 1995.
> 
> I don't think we can fully drop support for these systems.
> 
> Did they have an unique PCI ID or something else that could be tested
> for?

Floppy controllers are not PCI devices and thus have no PCI id
unfortunately... :-(

> Perhaps it could be just a white list like dmi_year > 1995 to disable.
> 
> Depending on how often floppies are still used this might save
> non trivial amounts of power on newer systems :)

Removing these calls will indeed save a *tiny* amount of power by
allowing the CPU to go into halt during DMA transfer. But the main
argument should be simplification.

> Anyways it would be probably good to convert this to the new infrastructure,
> and remove the old hooks, but the interrupt-context issue would
> need to be fixed first.
> 
> -Andi

Well, at least for testing whether it fixes the new problem (DMA cache
issue), it's useful to know that these calls can be safely removed on
almost all of today's machines. That way, we will know whether this
refactoring will be worth the effort.

Regards,

Alain

  reply	other threads:[~2009-12-28 10:34 UTC|newest]

Thread overview: 74+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <4AFB3962.2020106@ntlworld.com>
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     [not found]                                                                   ` <4B2A530D.3080606@knaff.lu>
2009-12-17 17:00                                                                     ` DMA cache consistency bug introduced in 2.6.28 (Was: Re: [Fdutils] Cannot format floppies under kernel 2.6.*?) Alain Knaff
2009-12-17 17:27                                                                       ` Linus Torvalds
2009-12-17 18:21                                                                         ` DMA cache consistency bug introduced in 2.6.28 Krzysztof Halasa
2009-12-17 20:46                                                                         ` DMA cache consistency bug introduced in 2.6.28 (Was: Re: [Fdutils] Cannot format floppies under kernel 2.6.*?) Alain Knaff
2009-12-17 21:14                                                                           ` Linus Torvalds
2009-12-17 22:11                                                                             ` Alain Knaff
2009-12-17 22:43                                                                               ` Linus Torvalds
2009-12-17 23:24                                                                                 ` Alain Knaff
2009-12-18  8:59                                                                                   ` Mark Hounschell
2009-12-18 10:55                                                                                     ` [Fdutils] DMA cache consistency bug introduced in 2.6.28 (Was: " Mark Hounschell
2009-12-18 15:01                                                                                       ` [Fdutils] DMA cache consistency bug introduced in 2.6.28 Krzysztof Halasa
2009-12-18 15:22                                                                                       ` [Fdutils] DMA cache consistency bug introduced in 2.6.28 (Was: Re: Cannot format floppies under kernel 2.6.*?) Linus Torvalds
2009-12-18 15:28                                                                                         ` Mark Hounschell
2009-12-18 15:45                                                                                           ` Linus Torvalds
2009-12-18 20:04                                                                                             ` Mark Hounschell
2009-12-18 20:15                                                                                               ` Linus Torvalds
2009-12-22 15:11                                                                                                 ` Mark Hounschell
2009-12-22 17:38                                                                                                   ` Linus Torvalds
2009-12-22 17:57                                                                                                     ` Mark Hounschell
2009-12-22 23:37                                                                                                       ` Pallipadi, Venkatesh
2009-12-23  0:22                                                                                                         ` Mark Hounschell
2009-12-23 13:02                                                                                                           ` Mark Hounschell
2009-12-23 15:10                                                                                                             ` Pallipadi, Venkatesh
2009-12-23 15:34                                                                                                               ` Mark Hounschell
2009-12-23 15:57                                                                                                                 ` Mark Hounschell
2009-12-23 16:31                                                                                                                 ` Linus Torvalds
2009-12-23 16:38                                                                                                                   ` [Fdutils] DMA cache consistency bug introduced in 2.6.28 Andi Kleen
2009-12-23 16:49                                                                                                                     ` Linus Torvalds
2009-12-23 17:08                                                                                                                       ` Andi Kleen
2009-12-25 12:21                                                                                                                         ` Arjan van de Ven
2009-12-25 20:33                                                                                                                           ` Andi Kleen
2009-12-26  9:38                                                                                                                             ` Arjan van de Ven
2009-12-26 16:40                                                                                                                               ` Andi Kleen
2009-12-27 12:28                                                                                                                                 ` Alain Knaff
2009-12-28  1:54                                                                                                                                   ` Andi Kleen
2009-12-28 10:27                                                                                                                                     ` Alain Knaff [this message]
2009-12-28 14:54                                                                                                                                       ` Andi Kleen
2009-12-27 11:09                                                                                                                         ` Pavel Machek
2009-12-28 20:54                                                                                                                           ` Mark Hounschell
2009-12-23 17:19                                                                                                                       ` Pallipadi, Venkatesh
2009-12-23 17:16                                                                                                                         ` Andi Kleen
2009-12-23 20:11                                                                                                                       ` alain
2009-12-23 17:41                                                                                                                     ` Mark Hounschell
2009-12-23 18:01                                                                                                                       ` Linus Torvalds
2009-12-23 18:11                                                                                                                         ` Mark Hounschell
2009-12-23 19:18                                                                                                                       ` Pallipadi, Venkatesh
2009-12-23 19:35                                                                                                                         ` Mark Hounschell
2009-12-23 20:30                                                                                                                           ` Pallipadi, Venkatesh
2009-12-23 20:34                                                                                                                             ` alain
2009-12-23 21:34                                                                                                                               ` Pallipadi, Venkatesh
2010-01-08 17:42                                                                                                                             ` Mark Hounschell
2010-01-12  0:19                                                                                                                               ` Pallipadi, Venkatesh
2010-01-12  9:04                                                                                                                                 ` Mark Hounschell
2010-01-15  2:01                                                                                                                                   ` Pallipadi, Venkatesh
2010-01-15  9:39                                                                                                                                     ` Mark Hounschell
2010-01-15 18:02                                                                                                                                     ` Mark Hounschell
2010-01-21 19:09                                                                                                                                       ` [PATCH] x86: Disable HPET MSI on ATI SB700/SB800 Pallipadi, Venkatesh
2010-01-22 22:00                                                                                                                                         ` [tip:x86/urgent] " tip-bot for Pallipadi, Venkatesh
2010-01-23  6:51                                                                                                                                         ` tip-bot for Pallipadi, Venkatesh
2010-01-23  7:21                                                                                                                                         ` [PATCH] " Yuhong Bao
2010-01-25 17:10                                                                                                                                           ` Andreas Herrmann
2010-01-28  9:17                                                                                                                                             ` Mark Hounschell
2010-01-28 13:25                                                                                                                                               ` Mark Hounschell
2010-01-28 13:41                                                                                                                                                 ` Borislav Petkov
2010-01-28 14:45                                                                                                                                                   ` Mark Hounschell
2010-05-17 14:59                                                                                                                                             ` Andreas Herrmann
2010-05-17 15:10                                                                                                                                               ` Yuhong Bao
2010-05-17 15:12                                                                                                                                               ` Linus Torvalds
2010-05-17 16:46                                                                                                                                                 ` Andreas Herrmann
2010-05-18  0:56                                                                                                                                               ` Robert Hancock
2010-05-18  1:02                                                                                                                                                 ` Linus Torvalds
2010-05-18  1:06                                                                                                                                                   ` Robert Hancock
2010-05-18  8:45                                                                                                                                                 ` Andi Kleen
2010-05-18 23:22                                                                                                                                                   ` Robert Hancock

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