From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 29943C433FE for ; Wed, 20 Apr 2022 10:07:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1377499AbiDTKJw (ORCPT ); Wed, 20 Apr 2022 06:09:52 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41986 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1377502AbiDTKJt (ORCPT ); Wed, 20 Apr 2022 06:09:49 -0400 Received: from metis.ext.pengutronix.de (metis.ext.pengutronix.de [IPv6:2001:67c:670:201:290:27ff:fe1d:cc33]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 800CE3EAA2 for ; Wed, 20 Apr 2022 03:07:04 -0700 (PDT) Received: from ptx.hi.pengutronix.de ([2001:67c:670:100:1d::c0]) by metis.ext.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1nh7Eh-0003GG-RX; Wed, 20 Apr 2022 12:06:59 +0200 Received: from sha by ptx.hi.pengutronix.de with local (Exim 4.92) (envelope-from ) id 1nh7Eh-0000fi-0s; Wed, 20 Apr 2022 12:06:59 +0200 Date: Wed, 20 Apr 2022 12:06:59 +0200 From: Sascha Hauer To: Codrin.Ciubotariu@microchip.com Cc: alsa-devel@alsa-project.org, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org, lars@metafoo.de, broonie@kernel.org, perex@perex.cz, tiwai@suse.com, robh+dt@kernel.org, Nicolas.Ferre@microchip.com Subject: Re: [PATCH v3 1/6] ASoC: dmaengine: do not use a NULL prepare_slave_config() callback Message-ID: <20220420100658.GU4012@pengutronix.de> References: <20220307122202.2251639-1-codrin.ciubotariu@microchip.com> <20220307122202.2251639-2-codrin.ciubotariu@microchip.com> <20220420091552.GD2387@pengutronix.de> <968f9bfb-bddf-a8f0-6d8f-18b92d865aa2@microchip.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <968f9bfb-bddf-a8f0-6d8f-18b92d865aa2@microchip.com> X-Sent-From: Pengutronix Hildesheim X-URL: http://www.pengutronix.de/ X-IRC: #ptxdist @freenode X-Accept-Language: de,en X-Accept-Content-Type: text/plain X-Uptime: 12:03:21 up 20 days, 22:33, 67 users, load average: 0.55, 0.31, 0.16 User-Agent: Mutt/1.10.1 (2018-07-13) X-SA-Exim-Connect-IP: 2001:67c:670:100:1d::c0 X-SA-Exim-Mail-From: sha@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: devicetree@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org On Wed, Apr 20, 2022 at 09:58:06AM +0000, Codrin.Ciubotariu@microchip.com wrote: > On 20.04.2022 12:15, Sascha Hauer wrote: > > EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe > > > > Hi, > > Hi Sascha, > > > > > On Mon, Mar 07, 2022 at 02:21:57PM +0200, Codrin Ciubotariu wrote: > >> Even if struct snd_dmaengine_pcm_config is used, prepare_slave_config() > >> callback might not be set. Check if this callback is set before using it. > >> > >> Fixes: fa654e085300 ("ASoC: dmaengine-pcm: Provide default config") > >> Signed-off-by: Codrin Ciubotariu > >> --- > >> > >> Changes in v2,v3: > >> - none > >> > >> sound/soc/soc-generic-dmaengine-pcm.c | 6 +++--- > >> 1 file changed, 3 insertions(+), 3 deletions(-) > >> > >> diff --git a/sound/soc/soc-generic-dmaengine-pcm.c b/sound/soc/soc-generic-dmaengine-pcm.c > >> index 285441d6aeed..2ab2ddc1294d 100644 > >> --- a/sound/soc/soc-generic-dmaengine-pcm.c > >> +++ b/sound/soc/soc-generic-dmaengine-pcm.c > >> @@ -86,10 +86,10 @@ static int dmaengine_pcm_hw_params(struct snd_soc_component *component, > >> > >> memset(&slave_config, 0, sizeof(slave_config)); > >> > >> - if (!pcm->config) > >> - prepare_slave_config = snd_dmaengine_pcm_prepare_slave_config; > >> - else > >> + if (pcm->config && pcm->config->prepare_slave_config) > >> prepare_slave_config = pcm->config->prepare_slave_config; > >> + else > >> + prepare_slave_config = snd_dmaengine_pcm_prepare_slave_config; > >> > >> if (prepare_slave_config) { > >> int ret = prepare_slave_config(substream, params, &slave_config); > > > > I wonder if this patch is correct. There are drivers like > > sound/soc/mxs/mxs-pcm.c which call snd_dmaengine_pcm_register() with a > > config which has the prepare_slave_config callback unset. For these > > drivers dmaengine_pcm_hw_params() previously was a no-op. Now with this > > patch snd_dmaengine_pcm_prepare_slave_config() and > > dmaengine_slave_config() are called. At least for the mxs-pcm driver > > calling dmaengine_slave_config() will return -ENOSYS. > > > > At least the "Check if this callback is set before using it" part is > > wrong, the callback is checked before using it with > > > > if (prepare_slave_config) { > > ... > > } > > > > I don't have any mxs hardware at hand to test this. I just stumbled upon > > the change of behaviour when rebasing > > https://patchwork.kernel.org/project/alsa-devel/patch/20220301122111.1073174-1-s.hauer@pengutronix.de/ > > on current master. > > You are right. I changed the behavior from: > if (pmc->config && !pcm->config->prepare_slave_config) > > to: > if (pmc->config && !pcm->config->prepare_slave_config) > snd_dmaengine_pcm_prepare_slave_config() > > It was not intended and I agree that the commit message is not accurate. > I guess some drivers might not need dmaengine_slave_config()... > However, in my case, for the mchp-pdmc driver, I do have pcm->config > with pcm->config->prepare_slave_config NULL, but I still need > snd_dmaengine_pcm_prepare_slave_config() to be called. Should we add a > separate flag to call snd_dmaengine_pcm_prepare_slave_config() if > pcm->config->prepare_slave_config is NULL? Other drivers set pcm->config->prepare_slave_config to snd_dmaengine_pcm_prepare_slave_config() explicitly: sound/soc/fsl/imx-pcm-dma.c:33: .prepare_slave_config = snd_dmaengine_pcm_prepare_slave_config, I think that's the way to go. Regards, Sascha -- Pengutronix e.K. | | Steuerwalder Str. 21 | http://www.pengutronix.de/ | 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |