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: Fri, 7 Dec 2001 17:03:41 +0300 [thread overview]
Message-ID: <20011207170341.A9959@jurassic.park.msu.ru> (raw)
In-Reply-To: <20011206061315.J13427@garloff.etpnet.phys.tue.nl> <20011206125935.A3930@jurassic.park.msu.ru> <20011207132505.B4229@garloff.etpnet.phys.tue.nl>
In-Reply-To: <20011207132505.B4229@garloff.etpnet.phys.tue.nl>; from garloff@suse.de on Fri, Dec 07, 2001 at 01:25:05PM +0100
On Fri, Dec 07, 2001 at 01:25:05PM +0100, Kurt Garloff wrote:
> So I wonder where the bug actually is. Somewhere in hardware; but I wonder
> whether the CMD646 or the 2117x (PYXIS/CIA) is to blame. The QLogicISP seems
> to happily do BM-DMA, so I'd point to the CMD646.
Hmm, it seems to be a pyxis bug; the hardware workaround exists, but
I guess that it might be not implemented properly on early miatas.
This also explains why I don't have that problem on lx164 and sx164.
>From pyxis manual:
"A.1 Read Page Problem
PCI DMA reads that attempt to cross 8K page boundaries cause data corruption
problems. A fix has been implemented with an Altera 7032 and two Pericom
PI5C3400 bus switches and a diode."
> OTOH, the QLogic sits on
> the 2nd PCI bus (32bit), which could make a difference as well.
Certainly - the 2nd bus is behind PCI-PCI bridge.
Ivan.
next prev parent reply other threads:[~2001-12-07 14:04 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
2001-12-07 12:25 ` Kurt Garloff
2001-12-07 14:03 ` Ivan Kokshaysky [this message]
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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