From mboxrd@z Thu Jan 1 00:00:00 1970 From: Risto Suominen Subject: Re: [PATCH 002/002] de2104x: support for systems lacking cache coherence Date: Mon, 9 Feb 2009 21:22:03 +0200 Message-ID: <46e1c7760902091122m6ec7fbb5nefd9cc9789880c0f@mail.gmail.com> References: <46e1c7760902071330i5362fe4fvd99fc7075fc666d3@mail.gmail.com> <46e1c7760902082327s1c498ac3w56939960ac306426@mail.gmail.com> <20090208.234502.197065045.davem@davemloft.net> <46e1c7760902090022g1d903ca0nf314f0c1cc6b07c8@mail.gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: David Miller , netdev@vger.kernel.org To: Krzysztof Halasa Return-path: Received: from mail-bw0-f161.google.com ([209.85.218.161]:41788 "EHLO mail-bw0-f161.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754127AbZBITWF (ORCPT ); Mon, 9 Feb 2009 14:22:05 -0500 Received: by bwz5 with SMTP id 5so1747375bwz.13 for ; Mon, 09 Feb 2009 11:22:03 -0800 (PST) In-Reply-To: Sender: netdev-owner@vger.kernel.org List-ID: 2009/2/9 Krzysztof Halasa : > > That means the consistent/coherent mapping isn't really > consistent/coherent (uncached), right? Perhaps there is some way to fix > this instead of changing the drivers to avoid the problematic area? > Yes. The other way could be to add a config parameter that allows to explicitly set CONFIG_NOT_COHERENT_CACHE. I have not tried this, probably because the necessary code wasn't in arch/powerpc until 2.6.21. Anyway, now I have tested with 2.6.24, and the problem still exists. Apropos changing the driver, I would like to point out, that leaving my proposed config parameter to its default value means not changing the driver. > Potentially any driver is affected by such coherency problem, this can't > be specific to 21040. > I agree. That talks for the config solution. Risto