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From: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
To: Kurt Garloff <garloff@suse.de>,
	Linux kernel list <linux-kernel@vger.kernel.org>
Subject: Re: IDE DMA on AXP & barriers
Date: Thu, 6 Dec 2001 12:59:35 +0300	[thread overview]
Message-ID: <20011206125935.A3930@jurassic.park.msu.ru> (raw)
In-Reply-To: <20011206061315.J13427@garloff.etpnet.phys.tue.nl>
In-Reply-To: <20011206061315.J13427@garloff.etpnet.phys.tue.nl>; from garloff@suse.de on Thu, Dec 06, 2001 at 06:13:15AM +0100

On Thu, Dec 06, 2001 at 06:13:15AM +0100, Kurt Garloff wrote:
> I would imagine that the following barriers are nacessary:
> * After setting up the IDE DMA tables (PRD) and having the data there,
>   we need to have a barrier before telling the controller to do DMA.

Actually, we have more than one - the memory barriers are hidden in outX()
macros.

> * After the controller is done with it, we need to make sure the
>   data is in mem before we use it (i.e. we need some mb() equiv on the
>   controller)

Sure, otherwise the controller just wouldn't work, and not only on alpha.
I never had any problems with IDE DMA on lx164 (which has exactly the same
IDE chip), but it was back in 2.3 or 2.4-test times...
Maybe something got broken since then - I could check this (if I find
a spare IDE drive).

Ivan.

  reply	other threads:[~2001-12-06 10:00 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2001-12-06  5:13 Kurt Garloff
2001-12-06  9:59 ` Ivan Kokshaysky [this message]
2001-12-07 12:25   ` Kurt Garloff
2001-12-07 14:03     ` Ivan Kokshaysky
2001-12-07 14:48       ` Kurt Garloff
2001-12-07 16:43         ` Ivan Kokshaysky
2001-12-07 17:02           ` Kurt Garloff
2001-12-07 18:50             ` Jay Estabrook

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