From mboxrd@z Thu Jan 1 00:00:00 1970 From: arnd@arndb.de (Arnd Bergmann) Date: Fri, 12 Aug 2011 14:53:05 +0200 Subject: [PATCH 7/9] ARM: DMA: steal memory for DMA coherent mappings In-Reply-To: <1313146711-1767-8-git-send-email-m.szyprowski@samsung.com> References: <1313146711-1767-1-git-send-email-m.szyprowski@samsung.com> <1313146711-1767-8-git-send-email-m.szyprowski@samsung.com> Message-ID: <201108121453.05898.arnd@arndb.de> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Friday 12 August 2011, Marek Szyprowski wrote: > > From: Russell King > > Steal memory from the kernel to provide coherent DMA memory to drivers. > This avoids the problem with multiple mappings with differing attributes > on later CPUs. > > Signed-off-by: Russell King > [m.szyprowski: rebased onto 3.1-rc1] > Signed-off-by: Marek Szyprowski Hi Marek, Is this the same patch that Russell had to revert because it didn't work on some of the older machines, in particular those using dmabounce? I thought that our discussion ended with the plan to use this only for ARMv6+ (which has a problem with double mapping) but not on ARMv5 and below (which don't have this problem but might need dmabounce). Arnd From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752110Ab1HLMxr (ORCPT ); Fri, 12 Aug 2011 08:53:47 -0400 Received: from moutng.kundenserver.de ([212.227.126.187]:54369 "EHLO moutng.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751870Ab1HLMxq (ORCPT ); Fri, 12 Aug 2011 08:53:46 -0400 From: Arnd Bergmann To: Marek Szyprowski Subject: Re: [PATCH 7/9] ARM: DMA: steal memory for DMA coherent mappings Date: Fri, 12 Aug 2011 14:53:05 +0200 User-Agent: KMail/1.12.2 (Linux/2.6.37; KDE/4.3.2; x86_64; ; ) Cc: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-media@vger.kernel.org, linux-mm@kvack.org, linaro-mm-sig@lists.linaro.org, Michal Nazarewicz , Kyungmin Park , Russell King , Andrew Morton , KAMEZAWA Hiroyuki , Ankita Garg , Daniel Walker , Mel Gorman , Jesse Barker , Jonathan Corbet , Shariq Hasnain , Chunsang Jeong References: <1313146711-1767-1-git-send-email-m.szyprowski@samsung.com> <1313146711-1767-8-git-send-email-m.szyprowski@samsung.com> In-Reply-To: <1313146711-1767-8-git-send-email-m.szyprowski@samsung.com> MIME-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-15" Content-Transfer-Encoding: 7bit Message-Id: <201108121453.05898.arnd@arndb.de> X-Provags-ID: V02:K0:6ajYTDi7dUGhOFy5raIsIxwGWCD4KeNkWlx8bLXJQ8J MajKLzQTzR71886sThEBOcqgiiOQcQWML2J3YAXQVKScSaRR2D EX3ofQYCMl+oF6tIqt8tWwilX9Sz2QCLxy1zgysCfwjb5Yx3Dy KMPOiZb1xCqz1kZ9mn4BtaGpDm7eHz/NfB++44We9DrYbw1ND9 Gn662OU3HLzTmQatOxpIw== Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Friday 12 August 2011, Marek Szyprowski wrote: > > From: Russell King > > Steal memory from the kernel to provide coherent DMA memory to drivers. > This avoids the problem with multiple mappings with differing attributes > on later CPUs. > > Signed-off-by: Russell King > [m.szyprowski: rebased onto 3.1-rc1] > Signed-off-by: Marek Szyprowski Hi Marek, Is this the same patch that Russell had to revert because it didn't work on some of the older machines, in particular those using dmabounce? I thought that our discussion ended with the plan to use this only for ARMv6+ (which has a problem with double mapping) but not on ARMv5 and below (which don't have this problem but might need dmabounce). Arnd From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail138.messagelabs.com (mail138.messagelabs.com [216.82.249.35]) by kanga.kvack.org (Postfix) with SMTP id 78929900138 for ; Fri, 12 Aug 2011 08:53:58 -0400 (EDT) From: Arnd Bergmann Subject: Re: [PATCH 7/9] ARM: DMA: steal memory for DMA coherent mappings Date: Fri, 12 Aug 2011 14:53:05 +0200 References: <1313146711-1767-1-git-send-email-m.szyprowski@samsung.com> <1313146711-1767-8-git-send-email-m.szyprowski@samsung.com> In-Reply-To: <1313146711-1767-8-git-send-email-m.szyprowski@samsung.com> MIME-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-15" Content-Transfer-Encoding: 7bit Message-Id: <201108121453.05898.arnd@arndb.de> Sender: owner-linux-mm@kvack.org List-ID: To: Marek Szyprowski Cc: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-media@vger.kernel.org, linux-mm@kvack.org, linaro-mm-sig@lists.linaro.org, Michal Nazarewicz , Kyungmin Park , Russell King , Andrew Morton , KAMEZAWA Hiroyuki , Ankita Garg , Daniel Walker , Mel Gorman , Jesse Barker , Jonathan Corbet , Shariq Hasnain , Chunsang Jeong On Friday 12 August 2011, Marek Szyprowski wrote: > > From: Russell King > > Steal memory from the kernel to provide coherent DMA memory to drivers. > This avoids the problem with multiple mappings with differing attributes > on later CPUs. > > Signed-off-by: Russell King > [m.szyprowski: rebased onto 3.1-rc1] > Signed-off-by: Marek Szyprowski Hi Marek, Is this the same patch that Russell had to revert because it didn't work on some of the older machines, in particular those using dmabounce? I thought that our discussion ended with the plan to use this only for ARMv6+ (which has a problem with double mapping) but not on ARMv5 and below (which don't have this problem but might need dmabounce). Arnd -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org