From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755189AbaENM0V (ORCPT ); Wed, 14 May 2014 08:26:21 -0400 Received: from smtp-out-164.synserver.de ([212.40.185.164]:1087 "EHLO smtp-out-123.synserver.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751527AbaENM0T (ORCPT ); Wed, 14 May 2014 08:26:19 -0400 X-SynServer-TrustedSrc: 1 X-SynServer-AuthUser: lars@laprican.de X-SynServer-PPID: 18873 Message-ID: <5373607D.2000200@metafoo.de> Date: Wed, 14 May 2014 14:24:29 +0200 From: Lars-Peter Clausen User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20131103 Icedove/17.0.10 MIME-Version: 1.0 To: Tushar Behera CC: Jassi Brar , Linux Kernel Mailing List , dmaengine@vger.kernel.org, Vinod Koul , Dan Williams Subject: Re: [PATCH] dma: pl330: Add support for DMA_PAUSE command References: <1400037830-21211-1-git-send-email-tushar.behera@linaro.org> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 05/14/2014 02:07 PM, Tushar Behera wrote: > On 14 May 2014 17:29, Jassi Brar wrote: >> On Wed, May 14, 2014 at 8:53 AM, Tushar Behera wrote: >>> While playing back audio, pmc_dmaengine requests the DMA channel to >>> stop DMA transmission through DMA_PAUSE command. >>> >>> Currently PL330 driver doesn't support DMA pause command, leaving >>> the DMA state inconsistent when the system resumes. Instead, it would >>> be better to terminate the DMA transfer during suspend and restart >>> again during resume. >>> >>> Tested with audio playback across a suspend-resume cycle. >>> >> What is pmc_dmaengine? How does DMA_PAUSE help, when there is no DMA_RESUME? >> > > Sorry, it is a typo. > > sound/core/pcm_dmaengine.c:snd_dmaengine_pcm_trigger() --> > dmaengine_pause() is called during system suspend. It is only called if the DMA driver has support for pausing and resuming DMA transfers. Or at least that is the intention. - Lars