From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753597Ab2GWOFZ (ORCPT ); Mon, 23 Jul 2012 10:05:25 -0400 Received: from mail-lb0-f174.google.com ([209.85.217.174]:54285 "EHLO mail-lb0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752769Ab2GWOFX (ORCPT ); Mon, 23 Jul 2012 10:05:23 -0400 Message-ID: <500D5A1F.9000808@linaro.org> Date: Mon, 23 Jul 2012 15:05:19 +0100 From: Lee Jones User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:14.0) Gecko/20120714 Thunderbird/14.0 MIME-Version: 1.0 To: Mark Brown CC: Liam Girdwood , alsa-devel@alsa-project.org, "linux-kernel@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" Subject: Help request - ASoC recursion issue Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Mark, I was wondering if I may bother you for some help. I've been having serious issues with testing the new mop500 sound system you have in your ASoC for-next branch. I've fixed a few issues and will be submitting patches shortly. The most serious issue I came across was with recursion. Let me show you: So here we setup the power_check function pointer with 'dapm_supply_check_power()'. > static struct snd_soc_dapm_widget * > snd_soc_dapm_new_control(struct snd_soc_dapm_context *dapm, > const struct snd_soc_dapm_widget *widget) > { > case snd_soc_dapm_regulator_supply: > case snd_soc_dapm_clock_supply: > w->power_check = dapm_supply_check_power; > break; > } Later we call 'dapm_widget_power_check()' which calls into the function pointer we know to be 'dapm_supply_check_power()'. > static int dapm_widget_power_check(struct snd_soc_dapm_widget *w) > { > if (w->power_checked) > return w->new_power; > > if (w->force) > w->new_power = 1; > else > w->new_power = w->power_check(w); > > w->power_checked = true; > > return w->new_power; > } The problem seems to be that 'dapm_supply_check_power()' then calls back into 'dapm_widget_power_check()'. Then round and round we go! > /* Check to see if a power supply is needed */ > static int dapm_supply_check_power(struct snd_soc_dapm_widget *w) > { > /* Check if one of our outputs is connected */ > list_for_each_entry(path, &w->sinks, list_source) { > DAPM_UPDATE_STAT(w, neighbour_checks); > > if (path->weak) > continue; > > if (path->connected && > !path->connected(path->source, path->sink)) > continue; > > if (!path->sink) > continue; > > if (dapm_widget_power_check(path->sink)) /* <-- Doh! */ > return 1; > } > } Can you shed some light on what the correct solution might be? Any help would be gratefully received. Kind regards, Lee -- Lee Jones Linaro ST-Ericsson Landing Team Lead Linaro.org │ Open source software for ARM SoCs Follow Linaro: Facebook | Twitter | Blog