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From: "H. Peter Anvin" <hpa@zytor.com>
To: Rene Herman <rene.herman@keyaccess.nl>
Cc: "David P. Reed" <dpreed@reed.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>,
	Alan Cox <alan@lxorguk.ukuu.org.uk>,
	Dmitry Torokhov <dtor_core@ameritech.net>,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH] x86: use explicit timing delay for pit accesses in kernel and pcspkr driver
Date: Mon, 18 Feb 2008 14:43:10 -0800	[thread overview]
Message-ID: <47BA09FE.50507@zytor.com> (raw)
In-Reply-To: <47BA0188.6000808@keyaccess.nl>

Rene Herman wrote:
>>
>> Uhm, I'm not sure I believe that's safe.
>>
>> The PIT is particularly pissy in this case -- the semantics of the PIT 
>> are ill-defined if there hasn't been a PIT clock between two adjacent 
>> accesses, so I fully expect that there are chipsets out there which 
>> will do very bad things in this case.
> 
> Okay. Now that they're isolated, do you have a suggestion for 
> {in,out}b_pit? You say a PIT clock, so do you think we can bounce of the 
> PIT iself in this case after all?

No, I don't think so.

	-hpa

  parent reply	other threads:[~2008-02-18 22:44 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-02-18 18:58 [PATCH] x86: use explicit timing delay for pit accesses in kernel and pcspkr driver David P. Reed
2008-02-18 20:17 ` Alan Cox
2008-02-18 20:38 ` Rene Herman
2008-02-18 20:43   ` H. Peter Anvin
2008-02-18 21:04     ` Rene Herman
2008-02-18 21:05       ` Rene Herman
2008-02-18 21:44       ` H. Peter Anvin
2008-02-18 21:59         ` Rene Herman
2008-02-18 22:01           ` H. Peter Anvin
2008-02-18 22:07             ` Rene Herman
2008-02-18 22:32               ` Rene Herman
2008-02-18 22:44                 ` H. Peter Anvin
2008-02-20 12:06                   ` Rene Herman
2008-02-20 17:05                     ` H. Peter Anvin
2008-02-20 17:09                       ` Rene Herman
2008-02-20 20:13                         ` [linux-kernel] " David P. Reed
2008-02-21  6:21                           ` Rene Herman
2008-02-18 22:43               ` H. Peter Anvin [this message]
2008-02-19  9:46 ` Ingo Molnar

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