From mboxrd@z Thu Jan 1 00:00:00 1970 From: Arnd Bergmann Subject: Re: [PATCH] asm-generic: add dma-mapping-linear.h Date: Mon, 1 Jun 2009 12:42:21 +0100 Message-ID: <200906011242.22026.arnd@arndb.de> References: <20090601082943.GA5550@flint.arm.linux.org.uk> <200906011141.33463.arnd@arndb.de> <20090601105851.GB25391@flint.arm.linux.org.uk> Mime-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Return-path: Received: from moutng.kundenserver.de ([212.227.126.177]:58192 "EHLO moutng.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756159AbZFALm2 (ORCPT ); Mon, 1 Jun 2009 07:42:28 -0400 In-Reply-To: <20090601105851.GB25391@flint.arm.linux.org.uk> Sender: linux-arch-owner@vger.kernel.org List-ID: To: Russell King Cc: FUJITA Tomonori , linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org On Monday 01 June 2009, Russell King wrote: > I didn't say "for all architectures". I said that the end conditions > need to be the same no matter how DMA is done. > > And yes, it does matter with some cache types. VIPT aliasing caches > and VIVT caches both need to ensure that condition is met, otherwise > userspace doesn't see the data. Ok, thanks for the explanation. > While we can hand-wave and say "some other part of the code should > handle this" I've had that disucssion several times, and that's where > this requirement eventually was stated. And, really, I'm not going > to re-discuss it yet again - I really don't have time or motivation > at present to be involved in yet another hand-waving egotistical > debate over it. I was not trying to start a debate over this, just being curious. Arnd <><