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From: Lee Revell <rlrevell@joe-job.com>
To: Max Krasnyansky <maxk@qualcomm.com>
Cc: george@mvista.com, john stultz <johnstul@us.ibm.com>,
	Greg KH <greg@kroah.com>,
	ganzinger@mvista.com, lkml <linux-kernel@vger.kernel.org>
Subject: Re: Calibration issues with USB disc present.
Date: Wed, 16 Nov 2005 19:30:23 -0500	[thread overview]
Message-ID: <1132187423.3008.21.camel@mindpipe> (raw)
In-Reply-To: <437BC8D6.4040402@qualcomm.com>

On Wed, 2005-11-16 at 16:03 -0800, Max Krasnyansky wrote:
> I think in the short term your best bet is to globally disable SMI at
> early
> boot stage (ie before TSC calibration).
> Some people might argue that it's not the most graceful solution
> because it might
> brake some BIOS features but it's a very common trick that is used by
> RT folks
> (for example RTAI has configurable option to enable SMI workaround)
> because
> on some chipset/BIOS combinations SMIs introduce horrible latencies.
> And you
> cannot do much about that other than disabling SMI.
> I have not seen any reports of negative side effects of disabling SMI
> yet. But
> if you're worried about that you could re-enable it later when you're
> done with
> TSC calibration and stuff.
> 

Hmm, interesting, I had no idea this was possible.  Is there a generic
way to disable SMI?  It would be useful for the -rt tree as lots of low
latency audio users have problems with SMI induced underruns.

Lee


  reply	other threads:[~2005-11-17  0:33 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2005-11-11 21:37 Calibration issues with USB disc present George Anzinger
2005-11-11 21:57 ` john stultz
2005-11-12  5:05   ` Greg KH
2005-11-12 16:06     ` George Anzinger
2005-11-12 21:33       ` Greg KH
2005-11-14 18:56         ` George Anzinger
2005-11-14 18:49           ` Greg KH
2005-11-14 19:46             ` Brad Campbell
2005-11-14 19:43               ` Greg KH
2005-11-14 19:58             ` john stultz
2005-11-14 21:52               ` George Anzinger
2005-11-17  0:03                 ` Max Krasnyansky
2005-11-17  0:30                   ` Lee Revell [this message]
2005-11-17 17:43                     ` Max Krasnyansky

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