From mboxrd@z Thu Jan 1 00:00:00 1970 From: =?ISO-8859-1?Q?P=E9ter?= Ujfalusi Subject: Re: [PATCH 05/10] ASoC: twl6040: One workqueue should be enough Date: Tue, 27 Sep 2011 09:33:06 +0300 Message-ID: <2417914.e6qfaNBTQp@barack> References: <1317043593-27202-1-git-send-email-peter.ujfalusi@ti.com> <20110926212914.GE2872@opensource.wolfsonmicro.com> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Return-path: Received: from na3sys009aog102.obsmtp.com (na3sys009aog102.obsmtp.com [74.125.149.69]) by alsa0.perex.cz (Postfix) with ESMTP id 6643E2437C for ; Tue, 27 Sep 2011 08:33:00 +0200 (CEST) Received: by mail-bw0-f54.google.com with SMTP id zs8so7933716bkb.41 for ; Mon, 26 Sep 2011 23:32:57 -0700 (PDT) In-Reply-To: <20110926212914.GE2872@opensource.wolfsonmicro.com> 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, Liam Girdwood , Misael Lopez Cruz List-Id: alsa-devel@alsa-project.org On Monday 26 September 2011 22:29:15 Mark Brown wrote: > On Mon, Sep 26, 2011 at 08:20:11PM +0300, Ujfalusi, Peter wrote: > > For the ramp code execution we should avoid any delay at all costs, > > since it can have audible side effects. > = > If you're that sensitive to latency does a workqueue offer sufficient > guarantees? It seams to be pretty good based on my tests. > > In my past experience the system wq can cause latency, since we usually > > have slow devices on it (GPS, proximity sensor, magnetometer, etc). > > Reading from those usually takes considerable amount of time, and > > we can end up with delayed execution of our ramp code. > = > How long are these work items taking? I'm wondering if the other work > items are taking sufficiently long to be actively disruptive if they > should be isolated from other things rather than the other way around. > Of course it could also be a large buildup of work... It could be any random driver (we can have random components on a device). This is just precaution to protect the audio from nasty things. -- P=E9ter