From mboxrd@z Thu Jan 1 00:00:00 1970 From: Russell King - ARM Linux Subject: Re: Highmem issues with MMC filesystem Date: Thu, 18 Mar 2010 09:23:52 +0000 Message-ID: <20100318092352.GD8267@n2100.arm.linux.org.uk> References: <037201cac5d7$6c5b8c60$LocalHost@wipblrx0099946> <043e01cac5df$c3ec1b90$LocalHost@wipblrx0099946> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from caramon.arm.linux.org.uk ([78.32.30.218]:37965 "EHLO caramon.arm.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751107Ab0CRJYM (ORCPT ); Thu, 18 Mar 2010 05:24:12 -0400 Content-Disposition: inline In-Reply-To: Sender: linux-mmc-owner@vger.kernel.org List-Id: linux-mmc@vger.kernel.org To: Nicolas Pitre Cc: Hemanth V , pierre@ossman.eu, linux-mmc@vger.kernel.org, linux-arm-kernel@lists.infradead.org On Wed, Mar 17, 2010 at 10:58:48AM -0400, Nicolas Pitre wrote: > On Wed, 17 Mar 2010, Hemanth V wrote: > > Nicolas, Russel are there any more details available which might help > > in investigating this further. > > The only conclusion I came to so far is that ARMv5 where highmem works > just fine in all cases has VIVT cache whereas ARMv6 has VIPT cache. > And the problem with VIPT caches occurs when direct DMA is involved, > otherwise there is no problem if PIO or NFS is used. Sprinkling some > flush_cache_all() in a few places makes things work, but this is not a > satisfactory solution. This sounds like the problem we had with the DMA API. Since that's now fixed, there shouldn't be a problem with the latest (-rc) kernels, or a kernel with my old streaming DMA patches applied.