From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752474AbcFEXQc (ORCPT ); Sun, 5 Jun 2016 19:16:32 -0400 Received: from mail.pqgruber.com ([178.189.19.235]:18512 "EHLO mail.pqgruber.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752023AbcFEXQb (ORCPT ); Sun, 5 Jun 2016 19:16:31 -0400 Date: Mon, 6 Jun 2016 01:16:26 +0200 From: Clemens Gruber To: Eric Nelson , Fabio Estevam , Mark Brown Cc: "alsa-devel@alsa-project.org" , linux-kernel Subject: Re: [alsa-devel] [PATCH] ASoC: sgtl5000: only check VDDD-supply, not revision Message-ID: <20160605231626.GA4076@archie.localdomain> References: <20160602124724.7725-1-clemens.gruber@pqgruber.com> <5751AEF6.40200@nelint.com> <575264A4.2070709@nelint.com> <20160604090324.GA867@archie.localdomain> <20160604171525.GA29266@archie.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20160604171525.GA29266@archie.localdomain> User-Agent: Mutt/1.6.1 (2016-04-27) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Eric, Fabio, Mark, On Sat, Jun 04, 2016 at 07:15:25PM +0200, Clemens Gruber wrote: > please don't merge the patch yet, I just observed a strange effect when > resetting the board during playback / just after playback stops. > At next boot time, sometimes the following error occurs: > imx-sgtl5000 sound: ASoc: CODEC DAI sgtl5000 not registered > imx-sgtl5000 sound: snd_soc_register_card failed (-517) I looked into this today and discovered the following: With my patch applied, if I reset the board just after playback, at the next boot, the sgtl5000_fill_defaults function does not succeed: Writing the default value 0x7060 to register 0x30 (CHIP_ANA_POWER) fails. How did CHIP_ANA_POWER change with my patch: Before, only LINREG_SIMPLE_POWERUP was cleared as is recommended in the datasheet when using the internal LDO, now both LINREG_SIMPLE_POWERUP and STARTUP_POWERUP are cleared, as is recommended when using external VDDD. But why does the SGTL5000 nack that default write to CHIP_ANA_POWER after a reboot, which interrupted the playback? The following patch from Eric solved the problem; one write fails but it continues setting the other registers and thus even if resetting a board during playback, the sound still works after reboot: http://mailman.alsa-project.org/pipermail/alsa-devel/2015-February/088356.html Another workaround might be to not even write a default value to CHIP_ANA_POWER, as in this patch from Eric: http://mailman.alsa-project.org/pipermail/alsa-devel/2015-February/088355.html What do you think we should do? Regards, Clemens