From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from metis.ext.pengutronix.de (metis.ext.pengutronix.de [92.198.50.35]) by ozlabs.org (Postfix) with ESMTP id 2EA05DE06B for ; Mon, 25 May 2009 06:35:17 +1000 (EST) Date: Sun, 24 May 2009 22:35:07 +0200 From: Wolfram Sang To: Jon Smirl Subject: Re: [PATCH V2 5/9] Main rewite of the mpc5200 audio DMA code Message-ID: <20090524203507.GA13491@pengutronix.de> References: <20090523231148.17919.46103.stgit@terra> <20090523231305.17919.12239.stgit@terra> <20090524185509.GA3561@pengutronix.de> <9e4733910905241310n59952fd2oaafd7f1363db324@mail.gmail.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="vtzGhvizbBRQ85DL" In-Reply-To: <9e4733910905241310n59952fd2oaafd7f1363db324@mail.gmail.com> Cc: linuxppc-dev@ozlabs.org, alsa-devel@alsa-project.org, broonie@sirena.org.uk List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , --vtzGhvizbBRQ85DL Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Sun, May 24, 2009 at 04:10:52PM -0400, Jon Smirl wrote: > On Sun, May 24, 2009 at 2:55 PM, Wolfram Sang wro= te: > >> Rewrite the mpc5200 audio DMA code to support both I2S and AC97. Make = it more robust. > > > > Why is it more robust? >=20 > I've implemented retries for when the AC97 hardware doesn't reset on > first try. About 10% of the time both the Efika and pcm030 AC97 codecs > don't reset on first try and need to be poked multiple times. Failure > is indicated by not having the link clock start ticking. Every once in > a while even five pokes won't get the link started and I have to power > cycle. >=20 > I don't have an oscilloscope, after I get these basic drivers in maybe > someone can put a scope on this and figure out why reset is failing. > I've read the various datasheets and I believe my reset pulses have > the correct timings. That's good to know. In fact, I think a summary of this should go into the patch description. --=20 Pengutronix e.K. | Wolfram Sang | Industrial Linux Solutions | http://www.pengutronix.de/ | --vtzGhvizbBRQ85DL Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.9 (GNU/Linux) iEYEARECAAYFAkoZr3sACgkQD27XaX1/VRthugCgyMk6m3VXlus5di2EBlMApObO y1QAn1fvipzt6UkqglM5xC1JMll/iGbV =7EUQ -----END PGP SIGNATURE----- --vtzGhvizbBRQ85DL--