From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751790Ab2AEJoN (ORCPT ); Thu, 5 Jan 2012 04:44:13 -0500 Received: from mail-iy0-f174.google.com ([209.85.210.174]:49290 "EHLO mail-iy0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750893Ab2AEJoD (ORCPT ); Thu, 5 Jan 2012 04:44:03 -0500 Date: Thu, 5 Jan 2012 17:54:15 +0800 From: Shawn Guo To: Richard Zhao Cc: Richard Zhao , Arnd Bergmann , patches@linaro.org, vinod.koul@intel.com, linux-kernel@vger.kernel.org, eric.miao@linaro.org, kernel@pengutronix.de, dan.j.williams@intel.com, linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH v3 2/2] dma/imx-sdma: use writel to write register when enable a channel Message-ID: <20120105095413.GD1729@S2101-09.ap.freescale.net> References: <1325750362-22598-1-git-send-email-richard.zhao@linaro.org> <1325750362-22598-3-git-send-email-richard.zhao@linaro.org> <20120105092316.GB1729@S2101-09.ap.freescale.net> <20120105091904.GO2414@b20223-02.ap.freescale.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20120105091904.GO2414@b20223-02.ap.freescale.net> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jan 05, 2012 at 05:19:05PM +0800, Richard Zhao wrote: > Russel mentioned that too. But I cannot understand. > If CONFIG_ARM_DMA_MEM_BUFFERABLE, readl/writel always call rmb/wmb. Do > we realy need it? It might affect performance. > For safety, I think we need it. The operations should be really fast. -- Regards, Shawn