From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jarkko Nikula Subject: Re: [PATCH 0/2] OMAP2+: DMA: fix src/dst position reporting Date: Tue, 01 Nov 2011 21:26:06 +0200 Message-ID: <4EB047CE.2010807@bitmer.com> References: <1320070817-9638-1-git-send-email-peter.ujfalusi@ti.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from bitmer.com ([213.157.87.50]:52116 "EHLO bitmer.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754223Ab1KAT0p (ORCPT ); Tue, 1 Nov 2011 15:26:45 -0400 In-Reply-To: <1320070817-9638-1-git-send-email-peter.ujfalusi@ti.com> Sender: linux-omap-owner@vger.kernel.org List-Id: linux-omap@vger.kernel.org To: Peter Ujfalusi Cc: Tony Lindgren , linux-omap@vger.kernel.org, alsa-devel@alsa-project.org On 10/31/2011 04:20 PM, Peter Ujfalusi wrote: > Hello, > > If the user asks for the sDMA current position before the first > data has been transmitted (before the first DMA request has been > generated), the reported position is not valid: > src position: CSAC is uninitialized > dst position: CDAC is 0 > > The return values in both case considered invalid. > This sitation can be identified by checking if the CDAC register > is 0 (it is initialized to 0 in omap_dam_start call). > In this case return the programmed source/destination address. > > The affected omap_get_dma_src_pos/omap_get_dma_dst_pos functions > are used by the audio stack mainly for checking the current position > of the audio stream. > > Regards, > Peter > --- > Peter Ujfalusi (2): > OMAP2+: DMA: Workaround for invalid source position > OMAP2+: DMA: Workaround for invalid destination position > > arch/arm/plat-omap/dma.c | 25 ++++++++++++++++++++++--- > 1 files changed, 22 insertions(+), 3 deletions(-) > Both, Reviewed-by: Jarkko Nikula