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 X-Spam-Level: X-Spam-Status: No, score=-7.9 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 90178C4338F for ; Fri, 6 Aug 2021 16:20:44 +0000 (UTC) Received: from alsa0.perex.cz (alsa0.perex.cz [77.48.224.243]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id DE22E611C9 for ; Fri, 6 Aug 2021 16:20:42 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org DE22E611C9 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.intel.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=alsa-project.org Received: from alsa1.perex.cz (alsa1.perex.cz [207.180.221.201]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by alsa0.perex.cz (Postfix) with ESMTPS id A9D1E16CF; Fri, 6 Aug 2021 18:19:50 +0200 (CEST) DKIM-Filter: OpenDKIM Filter v2.11.0 alsa0.perex.cz A9D1E16CF DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=alsa-project.org; s=default; t=1628266840; bh=1hmY7QBHkmCKoAaLu7UgnA06w2lR2gGTY7pMRZqdTOg=; h=Subject:To:References:From:Date:In-Reply-To:Cc:List-Id: List-Unsubscribe:List-Archive:List-Post:List-Help:List-Subscribe: From; b=jlH9pxguX2DXMBV1Nt4B6+/kzBhaXb9Ng8P/IuZcsMJBNjMeijasXFRUyuOOc44Tw PBaO5g/rTT06xIMgeEyBp6hGZlYjAsRgsOBRzsFLB52lCfzmZosCZKigyyWzZrCn9w 81iQ/XJUTGYVj4WfheWEdN2mHlRfFO5/sQfSDSSE= Received: from alsa1.perex.cz (localhost.localdomain [127.0.0.1]) by alsa1.perex.cz (Postfix) with ESMTP id 35483F8010A; Fri, 6 Aug 2021 18:19:50 +0200 (CEST) Received: by alsa1.perex.cz (Postfix, from userid 50401) id F249BF8025F; Fri, 6 Aug 2021 18:19:47 +0200 (CEST) Received: from mga09.intel.com (mga09.intel.com [134.134.136.24]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by alsa1.perex.cz (Postfix) with ESMTPS id 706C7F80169 for ; Fri, 6 Aug 2021 18:19:43 +0200 (CEST) DKIM-Filter: OpenDKIM Filter v2.11.0 alsa1.perex.cz 706C7F80169 X-IronPort-AV: E=McAfee;i="6200,9189,10068"; a="214381962" X-IronPort-AV: E=Sophos;i="5.84,301,1620716400"; d="scan'208";a="214381962" Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by orsmga102.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 06 Aug 2021 09:19:39 -0700 X-IronPort-AV: E=Sophos;i="5.84,301,1620716400"; d="scan'208";a="523552689" Received: from asobi-mobl1.amr.corp.intel.com (HELO [10.213.162.7]) ([10.213.162.7]) by fmsmga002-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 06 Aug 2021 09:19:38 -0700 Subject: Re: [PATCH] soundwire: intel: trap TRIGGER_SUSPEND in .trigger callback To: Vinod Koul References: <20210727053256.29949-1-yung-chuan.liao@linux.intel.com> <9ef7e341-13f4-69f7-964d-8e6efdd57ca7@linux.intel.com> From: Pierre-Louis Bossart Message-ID: Date: Fri, 6 Aug 2021 11:17:04 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Firefox/78.0 Thunderbird/78.11.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Cc: "alsa-devel@alsa-project.org" , Takashi Iwai , Ranjani Sridharan , "broonie@kernel.org" , Bard Liao , "Liao, Bard" X-BeenThere: alsa-devel@alsa-project.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: "Alsa-devel mailing list for ALSA developers - http://www.alsa-project.org" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: alsa-devel-bounces@alsa-project.org Sender: "Alsa-devel" On 8/6/21 8:37 AM, Vinod Koul wrote: > On 02-08-21, 10:46, Pierre-Louis Bossart wrote: >> >>>>>>>> The trigger callback is handled in the stream lock atomically, >>>>>>>> and are you sure that you want to operate a possibly heavy task there? >>>>>>> >>>>>>> It's a good objection that we didn't think of. >>>>>> >>>>>> Doesn't Intel use non atomic trigger to send IPCs which anyway >>>>>> involve code which can sleep..? >>>>> >>>>> sof_sdw.c doesn't seem setting it? >>>> >>>> Yes I think init_dai_link() should set it. Maybe Pierre/Bard would know why. >>> >>> init_dai_link() is to assign dai link elements only. No IPC is needed. >> >> The 'nonatomic' concept is only used for an FE dailink which expose a >> PCM device: >> >> soc-pcm.c: pcm->nonatomic = rtd->dai_link->nonatomic; >> >> Setting a BE dailink as 'nonatomic' would not accomplish much since BEs >> use the 'no_pcm' option. > > are no_pcm & nonatomic supposed to be not used together? So if FE is > nonatomic would BE trigger be atomic or nonatomic? I don't follow the multiple negations, so let me retry: For Intel machine drivers, all BE dailinks use .no_pcm = 1 (explicit setting) .nonatomic = 0 (implicit). All FE dailinks use .no_pcm = 0 (implicit) .nonatomic = 1 (explicit setting) >> So the question is: is there any issue with sending an IPC in a DAI >> trigger callback? > > Sorry looks like we diverged, orignal question was can we do heavy tasks > in trigger, the answer is no, unless one uses nonatomic flag which was > added so that people can do that work with DSPs like sending IPCs.. > Maybe we should add heavy slimbus/soundwire handling to it too...? I don't think the answer is as clear as you describe it Vinod. The .nonatomic field is at the BE dailink level. Unless I am missing something, I don't see anything that lets me set a .nonatomic property at the *DAI* level. The other problem is to define 'heavy task'. In this case, we are sending an IPC indeed, but the response is immediate, typically in the next ms tick. IOW, if the response time is in the ms order of magnitude, is this 'heavy'? >> This is not very different from sending a command on a >> bus btw, I see a similar example for SLIMbus devices: >> >> wcd9335.c: case SNDRV_PCM_TRIGGER_SUSPEND: >> wcd9335.c- case SNDRV_PCM_TRIGGER_PAUSE_PUSH: >> wcd9335.c- slim_stream_unprepare(dai_data->sruntime); >> wcd9335.c- slim_stream_disable(dai_data->sruntime); >> >> int slim_stream_unprepare(struct slim_stream_runtime *stream) >> { >> int i; >> >> for (i = 0; i < stream->num_ports; i++) >> slim_disconnect_port(stream, &stream->ports[i]); >> >> static int slim_disconnect_port(struct slim_stream_runtime *stream, >> struct slim_port *port) >> { >> struct slim_device *sdev = stream->dev; >> u8 wbuf[1]; >> struct slim_val_inf msg = {0, 1, NULL, wbuf, NULL}; >> u8 mc = SLIM_MSG_MC_DISCONNECT_PORT; >> DEFINE_SLIM_LDEST_TXN(txn, mc, 5, stream->dev->laddr, &msg); >> >> wbuf[0] = port->id; >> port->ch.state = SLIM_CH_STATE_DISCONNECTED; >> port->state = SLIM_PORT_DISCONNECTED; >> >> return slim_do_transfer(sdev->ctrl, &txn); >> } >> >> Such commands may take time... > > Agree, so users should be recommended to use nonatomic triggers. The SLIMbus example relies on DAIs as well, and this option does not exist, does it?