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From: Alan Cox <alan@redhat.com>
To: Tejun Heo <htejun@gmail.com>,
	linux-kernel@vger.kernel.org, linux-ide@vger.kernel.org,
	alan@redhat.com, jeff@garzik.org
Subject: Re: [PATCH] libata: Forcing PIO0 mode on reset must not freeze system
Date: Mon, 11 Feb 2008 06:32:06 -0500	[thread overview]
Message-ID: <20080211113206.GD28762@devserv.devel.redhat.com> (raw)
In-Reply-To: <20080211102907.GC4646@homac.suse.de>

On Mon, Feb 11, 2008 at 11:29:07AM +0100, Holger Macht wrote:
> > In the above example, even the reset sequence itself can cause hang if
> > the hardware is implemented slightly differently.  The reason why
> > set_piomode() locks up but reset sequence doesn't is simple dumb luck.
> 
> Another thing, whether it's poor luck or not, it worked like this than at
> least 2.6.22. And it was _heavily_ tested. The above commit broke it
> between 2.6.24-rc1 and 2.6.24-rc2, which is at least a regression.

Not neccessarily. It may just be timing chance on your box.

I agree however we should be doing the reset after the PIO0 switch if it
turns out that the precise order of the two events matters.

Alan


  parent reply	other threads:[~2008-02-11 11:32 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-02-10 19:55 Holger Macht
2008-02-11  2:37 ` Tejun Heo
2008-02-11 10:04   ` Holger Macht
2008-02-11 11:16     ` Tejun Heo
2008-02-11 11:28       ` Holger Macht
2008-02-11 13:11         ` Tejun Heo
2008-02-11 14:06           ` Holger Macht
2008-02-11 23:31             ` Tejun Heo
2008-02-14 12:42           ` Holger Macht
2008-02-11 11:25     ` Alan Cox
2008-02-11 10:29   ` Holger Macht
2008-02-11 10:49     ` Tejun Heo
2008-02-11 11:32     ` Alan Cox [this message]
2008-02-11 11:50   ` Alan Cox

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