From: Rene Herman <rene.herman@keyaccess.nl>
To: "H. Peter Anvin" <hpa@zytor.com>
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 23:32:27 +0100 [thread overview]
Message-ID: <47BA077B.50401@keyaccess.nl> (raw)
In-Reply-To: <47BA0188.6000808@keyaccess.nl>
On 18-02-08 23:07, Rene Herman wrote:
> On 18-02-08 23:01, H. Peter Anvin wrote:
>
>> Rene Herman wrote:
>>>
>>> Yes, but generally not any P5+ system is going to need the PIT delay
>>> in the first place meaning it just doesn't matter. There were the VIA
>>> issues with the PIC but unless I missed it not with the PIT.
>>>
>>
>> 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?
Am I correct that channel 1 is never used? A simple read from 0x41?
Rene.
next prev parent reply other threads:[~2008-02-18 22:31 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 [this message]
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
2008-02-19 9:46 ` Ingo Molnar
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