From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-yx0-f179.google.com (mail-yx0-f179.google.com [209.85.210.179]) by ozlabs.org (Postfix) with ESMTP id D2A3AB7B65 for ; Sun, 8 Nov 2009 05:20:17 +1100 (EST) Received: by yxe9 with SMTP id 9so2109028yxe.26 for ; Sat, 07 Nov 2009 10:20:15 -0800 (PST) MIME-Version: 1.0 Sender: glikely@secretlab.ca In-Reply-To: <20091107181153.GA31789@sirena.org.uk> References: <20091107081631.18908.82921.stgit@angua> <20091107083448.18908.80366.stgit@angua> <20091107181153.GA31789@sirena.org.uk> From: Grant Likely Date: Sat, 7 Nov 2009 11:19:54 -0700 Message-ID: Subject: Re: [alsa-devel] [PATCH 6/6] ASoC/mpc5200: Add fudge factor to value reported by .pointer() To: Mark Brown Content-Type: text/plain; charset=ISO-8859-1 Cc: alsa-devel@alsa-project.org, linuxppc-dev@lists.ozlabs.org, lrg@slimlogic.co.uk List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , 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. --=20 Grant Likely, B.Sc., P.Eng. Secret Lab Technologies Ltd.