From mboxrd@z Thu Jan 1 00:00:00 1970 From: Chris Snook Subject: Re: atl1 driver corrupting memory? Date: Wed, 25 Jul 2007 17:22:01 -0400 Message-ID: <46A7BEF9.1000600@redhat.com> References: <46A79790.6050203@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: Jay Cliburn , Netdev To: Chuck Ebbert Return-path: Received: from mx1.redhat.com ([66.187.233.31]:49374 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752312AbXGYVWE (ORCPT ); Wed, 25 Jul 2007 17:22:04 -0400 In-Reply-To: <46A79790.6050203@redhat.com> Sender: netdev-owner@vger.kernel.org List-Id: netdev.vger.kernel.org Chuck Ebbert wrote: > I have a report of random errors when using the atl1 driver > with kernel 2.6.22.1. Could that be a problem fixed by the > recent changes to DMA setup in 2.6.23-rc? I hope so. As far as we can tell the driver and the NIC itself are doing the right thing, and the pci layer or chipset is screwing up the 64-bit DMA. This only manifests when physical memory addresses cross the 4 GB boundary, and as far as I'm aware atl1 is only used on desktop boards, so we don't have a lot of testers. If someone wants to buy me and Jay more RAM so we can test it ourselves, I guess we wouldn't object :) I favor disabling 64-bit DMA in atl1 until Atheros can track this down in the lab. If we don't get confirmation that this bug is fixed by the DMA changes, I think we should revert to 32-bit DMA for 2.6.23. Limiting ourselves to 32-bit DMA on desktop systems is a lot less bad than allowing arbitrary memory corruption. -- Chris