From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ezequiel Garcia Subject: Re: [PATCH] ASoC: max98357a: Fix speaker pop when starting playback Date: Tue, 27 Mar 2018 15:11:57 -0300 Message-ID: <1522174317.2289.8.camel@collabora.com> References: <20180321223015.32173-1-ezequiel@vanguardiasur.com.ar> <20180322015456.GZ2186@sirena.org.uk> <1521723692.1890.1.camel@collabora.com> <20180327113631.GB29239@sirena.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from bhuna.collabora.co.uk (bhuna.collabora.co.uk [46.235.227.227]) by alsa0.perex.cz (Postfix) with ESMTP id 59B6F267063 for ; Tue, 27 Mar 2018 20:12:57 +0200 (CEST) In-Reply-To: <20180327113631.GB29239@sirena.org.uk> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: alsa-devel-bounces@alsa-project.org Sender: alsa-devel-bounces@alsa-project.org To: Mark Brown Cc: alsa-devel@alsa-project.org, Liam Girdwood , Stephen Barber , Mac Chiang , Ezequiel Garcia , kernel@collabora.com List-Id: alsa-devel@alsa-project.org On Tue, 2018-03-27 at 19:36 +0800, Mark Brown wrote: > On Thu, Mar 22, 2018 at 10:01:32AM -0300, Ezequiel Garcia wrote: > > On Thu, 2018-03-22 at 09:54 +0800, Mark Brown wrote: > > > On Wed, Mar 21, 2018 at 07:30:15PM -0300, Ezequiel Garcia wrote: > > > > +- sdmode-delay : specify a delay time for SD_MODE pin. > > > > According > > > > + to the DAC datasheet, if LRCLK is removed while BCLK > > > > is > > > > present, > > > > + the DAC output can cause loud pop/crack noises. This > > > > property > > > > + specifies a delay for the SD_MODE pin assert, required > > > > to > > > > + eliminate the noise. > > > Why is this configurable? This sounds like something entirely > > > within > > > the digital domain of the device rather than something that > > > depends > > > on > > > board configuration and it's hard to see how someone would > > > configure > > > this. > > The amount of delay needed seems specific to the CPU DAI, > > not specific to the DAC. The CPU DAIs or the machine > > could specify this as a parameter, but I can't don't see how. > > This sounds like it's just trying to reimplement the digital mute > feature we already have, it sounds more like what you're seeing is > noise > playing out of the SoC at the start of playback due to startup issues > or non-flushed FIFOs. Can you try implementing there please? > OK, I'll see how it goes using digital mute. Please discard v2 then. Thanks, Eze