From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759998AbbCDMgv (ORCPT ); Wed, 4 Mar 2015 07:36:51 -0500 Received: from mga14.intel.com ([192.55.52.115]:23986 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759235AbbCDMgt (ORCPT ); Wed, 4 Mar 2015 07:36:49 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.09,687,1418112000"; d="scan'208";a="535936347" Date: Wed, 4 Mar 2015 18:03:37 +0530 From: Vinod Koul To: Qiao Zhou Cc: dan.j.williams@intel.com, dmaengine@vger.kernel.org, linux-kernel@vger.kernel.org, zhangfei.gao@linaro.org Subject: Re: [PATCH v2] dma: mmp-tdma: refine dma disable and dma-pos update Message-ID: <20150304123337.GQ2613@intel.com> References: <1425345368-7708-1-git-send-email-zhouqiao@marvell.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1425345368-7708-1-git-send-email-zhouqiao@marvell.com> 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 Tue, Mar 03, 2015 at 09:16:08AM +0800, Qiao Zhou wrote: > Below are the refinements. > 1. Set DMA abort bit when disabling dma channel. This will clear > the remaining data in dma FIFO, to fix channel-swap issue. > 2. Read DMA HW pointer when updating DMA status. Previously dma > position is calculated by adding one period size in dma interrupt. > This is inaccurate/insufficient for some high-quality audio APP. > Since interrupt bottom half handler has variable schedule delay, > it causes big error when calculating sample delay. Read the actual > HW pointer and feedback can improve the accuracy. > 3. Do some minor code clean. Applied, thanks -- ~Vinod