From mboxrd@z Thu Jan 1 00:00:00 1970 From: Peter Ujfalusi Subject: Re: [RFC] dmaengine: omap-dma: Allow DMA controller to prefetch data Date: Mon, 19 Nov 2012 11:00:15 +0100 Message-ID: <50AA032F.1010102@ti.com> References: <20121018222046.GA28541@animalcreek.com> <20121018225540.GB28061@n2100.arm.linux.org.uk> <20121018232405.GA29064@animalcreek.com> <20121018233335.GC28061@n2100.arm.linux.org.uk> <50814B83.7090203@ti.com> <20121117113159.GM3332@n2100.arm.linux.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Received: from bear.ext.ti.com ([192.94.94.41]:51381 "EHLO bear.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753315Ab2KSKBF (ORCPT ); Mon, 19 Nov 2012 05:01:05 -0500 In-Reply-To: <20121117113159.GM3332@n2100.arm.linux.org.uk> Sender: linux-omap-owner@vger.kernel.org List-Id: linux-omap@vger.kernel.org To: Russell King - ARM Linux Cc: "Mark A. Greer" , linux-omap@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Jarkko Nikula On 11/17/2012 12:31 PM, Russell King - ARM Linux wrote: > On Fri, Oct 19, 2012 at 02:45:55PM +0200, P=E9ter Ujfalusi wrote: >> Hi, >> >> On 10/19/2012 01:33 AM, Russell King - ARM Linux wrote: >>> I'm merely pointing out here that we need their feedback here befor= e >>> deciding if there's anything further that needs to happen. >> >> Thanks Russell, I'll take a look at the implication of the prefetch = for audio. >=20 > P=E9ter, any news? Sorry, I was carried away with other things... I did some testing with and without the dma prefetch for audio (on Beag= leBoard with mplayer: -ao alsa/pulse). When we have prefetch enabled we tend to resume after pause from a slig= htly off place than when the prefetch is disabled. I also remember that in n9 we have had some issue with the DMA prefetch= =2E So I would for sure enable the prefetch for non cyclic DMA. =46or the cyclic I would not enable it for now. I need to dig a bit dee= per in DMA/McBSP to have better view on the issue. I have one comment to the patch itself as well. --=20 P=E9ter -- To unsubscribe from this list: send the line "unsubscribe linux-omap" i= n the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html