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=-1.0 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 3DA95C433E0 for ; Wed, 24 Jun 2020 17:34:16 +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 BE46F206C0 for ; Wed, 24 Jun 2020 17:34:15 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=alsa-project.org header.i=@alsa-project.org header.b="ssMLET5o" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org BE46F206C0 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.de Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=alsa-devel-bounces@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 501101886; Wed, 24 Jun 2020 19:33:24 +0200 (CEST) DKIM-Filter: OpenDKIM Filter v2.11.0 alsa0.perex.cz 501101886 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=alsa-project.org; s=default; t=1593020054; bh=TUYNYcG324mutIxlaUwfBS8RTAsvAs2zCmDlJT2y3Q8=; h=Date:From:To:Subject:In-Reply-To:References:Cc:List-Id: List-Unsubscribe:List-Archive:List-Post:List-Help:List-Subscribe: From; b=ssMLET5obiYhgHnFqDZcb96f8jgOZUMTe4nrgxfBq4TNCPc5ozMn4kNGYlMjSF99K BpnO/TAtybn56NRaFs+wNP2OLs9CgIGNnV7+NhWA6BTHaTOc2Uj8MDyLzcs9qPS6eE gVxp/yCTzUEJHhySg9QsVdYjkv/Dtd9A9De/5cCU= Received: from alsa1.perex.cz (localhost.localdomain [127.0.0.1]) by alsa1.perex.cz (Postfix) with ESMTP id C8608F8015A; Wed, 24 Jun 2020 19:33:23 +0200 (CEST) Received: by alsa1.perex.cz (Postfix, from userid 50401) id B36B5F8015B; Wed, 24 Jun 2020 19:33:22 +0200 (CEST) Received: from mx2.suse.de (mx2.suse.de [195.135.220.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by alsa1.perex.cz (Postfix) with ESMTPS id 6E38DF800B2 for ; Wed, 24 Jun 2020 19:33:14 +0200 (CEST) DKIM-Filter: OpenDKIM Filter v2.11.0 alsa1.perex.cz 6E38DF800B2 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 5B7FBAD87; Wed, 24 Jun 2020 17:33:13 +0000 (UTC) Date: Wed, 24 Jun 2020 19:33:13 +0200 Message-ID: From: Takashi Iwai To: Pierre-Louis Bossart Subject: Re: [PATCH] ALSA: hda/hdmi: Add Intel silent stream support In-Reply-To: <2404f45d-832d-69a0-fb3b-1981ae455f50@linux.intel.com> References: <1592954796-12449-1-git-send-email-harshapriya.n@intel.com> <7dd38f98-e74a-94c0-6888-523e6189c00b@linux.intel.com> <2404f45d-832d-69a0-fb3b-1981ae455f50@linux.intel.com> User-Agent: Wanderlust/2.15.9 (Almost Unreal) SEMI/1.14.6 (Maruoka) FLIM/1.14.9 (=?UTF-8?B?R29qxY0=?=) APEL/10.8 Emacs/25.3 (x86_64-suse-linux-gnu) MULE/6.0 (HANACHIRUSATO) MIME-Version: 1.0 (generated by SEMI 1.14.6 - "Maruoka") Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Cc: Harsha Priya , kai.vehmanen@intel.com, alsa-devel@alsa-project.org, Emmanuel Jillela 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 Wed, 24 Jun 2020 19:05:14 +0200, Pierre-Louis Bossart wrote: > > > > On 6/24/20 11:43 AM, Takashi Iwai wrote: > > On Wed, 24 Jun 2020 17:33:45 +0200, > > Pierre-Louis Bossart wrote: > >> > >> > >>>>> The silent stream is enabled with a Kconfig option, as well as a kernel > >>>>> parameter should there be a need to override the build time default. > >>>> > >>>> I'm not sure whether the module option is the best interface. > >>>> An alternative is a mixer element that controls dynamically.  Then > >>>> it'll be per card unlike the module option. > >>> > >>> +1, kcontrol seems the appropriate way to control this. > >> > >> It was my suggestion to use Kconfig+kernel parameter for > >> simplicity/overrides. > >> > >> The kcontrol is a nice idea, but in practice we typically only have > >> one card dealing with HDMI. > > > > Not really. There are systems with two HDMI outputs from both > > integrated and discrete GPUs. Most modern systems are only with > > hybrid graphics, though. > > Ok, maybe I am mistaken, in most of the HDMI issues we've seen only > one HDMI source. > > But it's a good point that this is only supposed to be used for Intel > whether it's a kernel parameter or a kcontrol shouldn't this be > dependent on a PCI ID being detected and a SKYLAKE flag being set? > it's my understanding that this applies from Skylake to TigerLake, not > before. I guess we can check it from the codec ID? Change the probe function for Skylake+ codecs to patch_i915_skl_hdmi and co, and set the flag there. > >> It also doesn't have a UCM representation > >> so would force the use of amixer and manual configs, or the UCM file > >> would always set the mode. > > > > But people usually use the distro kernels, so the situation is more or > > less equivalent; you'd have to adjust a module option manually if you > > want a different one from the default, and you'd have to be root to > > change it. > > > > So, rather the question is how we should provide the setup of such > > parameter. It's supposed to be a part of power management stuff that > > should be touched by either a smart PM tool or a manual override such > > as runtime PM setup? Or can it be seen as a more casual tuning? > > I am not aware of such tools. The only thing I know is that some of > the HDaudio power settings are already controlled by kernel > parameters, e.g. > > /etc/modprobe.d/audio_powersave.conf > options snd_hda_intel power_save=1 Yes, it's been the primary knob for years to turn on/off the runtime PM for HD-audio and other legacy drivers. This was used by powertop or some other power-aware daemons and tools, to be toggled dynamically per the power cable state or such. And, how the silent stream feature should be seen? Should it be a system-wide root-only setup or adjustable per user? Would it be changed often? Such questions and answers will lead us to the right direction, I hope. Takashi