From mboxrd@z Thu Jan 1 00:00:00 1970 From: Grant Likely Subject: Re: [PATCH 6/6] ASoC/mpc5200: Add fudge factor to value reported by .pointer() Date: Sat, 7 Nov 2009 11:19:54 -0700 Message-ID: References: <20091107081631.18908.82921.stgit@angua> <20091107083448.18908.80366.stgit@angua> <20091107181153.GA31789@sirena.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Return-path: Received: from mail-yx0-f196.google.com (mail-yx0-f196.google.com [209.85.210.196]) by alsa0.perex.cz (Postfix) with ESMTP id F40AB24677 for ; Sat, 7 Nov 2009 19:20:15 +0100 (CET) Received: by yxe34 with SMTP id 34so1736401yxe.16 for ; Sat, 07 Nov 2009 10:20:14 -0800 (PST) In-Reply-To: <20091107181153.GA31789@sirena.org.uk> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: alsa-devel-bounces@alsa-project.org Errors-To: alsa-devel-bounces@alsa-project.org To: Mark Brown Cc: alsa-devel@alsa-project.org, linuxppc-dev@lists.ozlabs.org, lrg@slimlogic.co.uk List-Id: alsa-devel@alsa-project.org On Sat, Nov 7, 2009 at 11:11 AM, Mark Brown wrote: > On Sat, Nov 07, 2009 at 01:34:55AM -0700, Grant Likely wrote: >> ALSA playback seems to be more reliable if the .pointer() hook reports >> a value slightly into the period, rather than right on the period >> boundary. =A0This patch adds a fudge factor of 1/4 the period size >> to better estimate the actual position of the DMA engine in the >> audio buffer. > > It occurs to me that in terms of dealing with what's going on here this > probably is achieving exactly the same effect as Jon's code in that it > tells ALSA that things are a bit ahead of where the buffer started. Possibly, but I can both reproduce and eliminate the problem Jon is seeing regardless of whether or not this patch, so I'm not yet convinced. g. -- = Grant Likely, B.Sc., P.Eng. Secret Lab Technologies Ltd.