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From: Dave Jones <davej@redhat.com>
To: Srivatsa Vaddagiri <vatsa@in.ibm.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>,
	lkcd-devel@lists.sourceforge.net,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	linux-ide@vger.kernel.org
Subject: Re: [PATCH] Poll-based IDE driver
Date: Wed, 8 Oct 2003 13:15:23 +0100	[thread overview]
Message-ID: <20031008121523.GH705@redhat.com> (raw)
In-Reply-To: <20031008174458.A32517@in.ibm.com>

On Wed, Oct 08, 2003 at 05:44:58PM +0530, Srivatsa Vaddagiri wrote:

 > > Why not just use udelay() ?  The above code cannot possibly do
 > > the right thing on all processors.
 > 
 > Since my code is supposed to run when system is crashing, I would like 
 > to avoid calling any function in the kernel as far as possible, since 
 > the kernel and its data structures may be in a inconsistent state 
 > and/or corrupted.

By the same principle, your dump_udelay() is just as likely to get
stomped on as the kernels udelay() function.
 
 > I do realize that the above code does not provide accurate 
 > delay and may not work on all platforms. In that direction
 > I was considering using the loops_per_jiffy variable 
 > which may provide more accurate/platform-independent delay (?) ..

If you must reinvent a wheel, use a round one. Copy udelay().

		Dave

-- 
 Dave Jones     http://www.codemonkey.org.uk

  reply	other threads:[~2003-10-08 12:15 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2003-09-17  9:11 [PATCH] Poll-based IDE dump driver for LKCD Srivatsa Vaddagiri
2003-09-17 13:55 ` Alan Cox
2003-10-08  9:43   ` [PATCH] Poll-based IDE driver Srivatsa Vaddagiri
2003-10-08 11:50     ` Dave Jones
2003-10-08 12:14       ` Srivatsa Vaddagiri
2003-10-08 12:15         ` Dave Jones [this message]
2003-10-08 13:26         ` Russell King
2003-10-08 18:34         ` [lkcd-devel] " Stephen Hemminger
2003-10-08 21:48         ` Alan Cox
2003-10-08 23:43           ` Jamie Lokier
2003-10-08 16:36       ` Andre Hedrick
2003-10-08 16:48         ` Dave Jones
2003-10-09  6:57           ` Andre Hedrick
2003-10-08 21:47     ` Alan Cox
2003-10-09  7:06       ` Andre Hedrick
2003-10-13 17:41         ` PRD Table id ol
2003-10-15 20:46           ` Alan Cox
2003-10-16 11:47           ` Andre Hedrick

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