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Date: Sat, 29 Sep 2001 20:27:52 +0100
From: Steve Maughan <saxm@dcs.ed.ac.uk>
To: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: George Garvey <tmwg-linuxknl@inxservices.com>,
        linux-kernel@vger.kernel.org
Subject: Re: 2.4.9-ac10 IDE access slows as uptime increases
Message-ID: <20010929202752.A25602@ummagumma>
In-Reply-To: <20010928204612.A911@inxservices.com> <E15nLB7-00027t-00@the-village.bc.nu>
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* Alan Cox (alan@lxorguk.ukuu.org.uk) wrote:
> Second question is what is in your IDE logs. The IDE layer will change
> down speeds when it hits a repeated problem (eg a DMA timeout) so if
> need be will switch back to PIO or to MWDMA.

I have what sounds like a similar problem - assuming it is a problem
with the IDE layer dropping the speed - except mine is with my CD or
DVD drive. They run a lot slower under the 2.4.x kernels than under
2.2.19 (looking at 2-3megs/s under 2.4.x, 5-7megs/s under 2.2.19).

Also when using 2.4.x, the kernel has a habit of disabling DMA and
performance plummets. Yet it is fine with 2.2.19.

Is this a related issue? Is there a fix for this?

Steve Maughan