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=-4.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 0F728C282D7 for ; Wed, 30 Jan 2019 09:35:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C43DD20882 for ; Wed, 30 Jan 2019 09:35:45 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=nvidia.com header.i=@nvidia.com header.b="RNax8oLO" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730265AbfA3Jfo (ORCPT ); Wed, 30 Jan 2019 04:35:44 -0500 Received: from hqemgate15.nvidia.com ([216.228.121.64]:10492 "EHLO hqemgate15.nvidia.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726427AbfA3Jfn (ORCPT ); Wed, 30 Jan 2019 04:35:43 -0500 Received: from hqpgpgate102.nvidia.com (Not Verified[216.228.121.13]) by hqemgate15.nvidia.com (using TLS: TLSv1.2, DES-CBC3-SHA) id ; Wed, 30 Jan 2019 01:35:13 -0800 Received: from hqmail.nvidia.com ([172.20.161.6]) by hqpgpgate102.nvidia.com (PGP Universal service); Wed, 30 Jan 2019 01:35:41 -0800 X-PGP-Universal: processed; by hqpgpgate102.nvidia.com on Wed, 30 Jan 2019 01:35:41 -0800 Received: from [10.26.11.176] (10.124.1.5) by HQMAIL101.nvidia.com (172.20.187.10) with Microsoft SMTP Server (TLS) id 15.0.1395.4; Wed, 30 Jan 2019 09:35:37 +0000 Subject: Re: [PATCH] ALSA: hda/tegra: enable clock during probe To: Sameer Pujar , Takashi Iwai CC: , , , , , , References: <1548351403-1875-1-git-send-email-spujar@nvidia.com> <06c00ce1-32ed-8aa9-0340-d00202a8fa62@nvidia.com>

<1f4c5185-e518-5674-4a8c-4e7db64aa0d3@nvidia.com> From: Jon Hunter Message-ID: Date: Wed, 30 Jan 2019 09:35:35 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.4.0 MIME-Version: 1.0 In-Reply-To: X-Originating-IP: [10.124.1.5] X-ClientProxiedBy: HQMAIL108.nvidia.com (172.18.146.13) To HQMAIL101.nvidia.com (172.20.187.10) Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: quoted-printable DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nvidia.com; s=n1; t=1548840913; bh=Nxe4ULhCqwrnlcVCbBZ7Bh0n4O1Eoo4OwxAjTp5vngo=; h=X-PGP-Universal:Subject:To:CC:References:From:Message-ID:Date: User-Agent:MIME-Version:In-Reply-To:X-Originating-IP: X-ClientProxiedBy:Content-Type:Content-Language: Content-Transfer-Encoding; b=RNax8oLOrgvpsisb16UnbVSDPXUPqTBEE47Fa4hoNe/Hx6JKuQ46jmZsolIE3A7gP 33eoZvT/uRzND+a5QXsi+qnBTmgK3ORxJHR34aQOUVxdg9os64ITS7U34la4GiO/8T 0O1caCJG+Ry+QmaARhPhDMimihYV6KObQC/bgcQmFPSywurNTCAE7HoNzOGh+BdAFi CajItCKxsmUiNve4N5+WnoxYpMM7b2dKJebjDy6a3bFIUnm/LHIgXtcEOMTER7YmRs DUxPoIJ4DSIHnm2k4dXoZCswhT0XWmBSZVKFsRiXhFuHBVm2GucsSbI976FDjRRJwp 1DPNHg7dmIs3A== Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 28/01/2019 06:06, Sameer Pujar wrote: >=20 > On 1/25/2019 7:34 PM, Jon Hunter wrote: >> On 25/01/2019 13:58, Takashi Iwai wrote: >>> On Fri, 25 Jan 2019 14:26:27 +0100, >>> Jon Hunter wrote: >>>> >>>> On 25/01/2019 12:40, Takashi Iwai wrote: >>>>> On Fri, 25 Jan 2019 12:36:00 +0100, >>>>> Jon Hunter wrote: >>>>>> >>>>>> On 24/01/2019 19:08, Takashi Iwai wrote: >>>>>>> On Thu, 24 Jan 2019 18:36:43 +0100, >>>>>>> Sameer Pujar wrote: >>>>>>>> If CONFIG_PM is disabled or runtime PM calls are forbidden, the >>>>>>>> clocks >>>>>>>> will not be ON. This could cause issue during probe, where hda ini= t >>>>>>>> setup is done. This patch checks whether runtime PM is enabled >>>>>>>> or not. >>>>>>>> If disabled, clocks are enabled in probe() and disabled in remove(= ) >>>>>>>> >>>>>>>> This patch does following minor changes as cleanup, >>>>>>>> =C2=A0=C2=A0 * return code check for pm_runtime_get_sync() to take= care of >>>>>>>> failure >>>>>>>> =C2=A0=C2=A0=C2=A0=C2=A0 and exit gracefully. >>>>>>>> =C2=A0=C2=A0 * In remove path runtime PM is disabled before callin= g >>>>>>>> snd_card_free(). >>>>>>>> =C2=A0=C2=A0 * hda_tegra_disable_clocks() is moved out of CONFIG_P= M_SLEEP >>>>>>>> check. >>>>>>>> =C2=A0=C2=A0 * runtime PM callbacks moved out of CONFIG_PM check >>>>>>>> >>>>>>>> Signed-off-by: Sameer Pujar >>>>>>>> Reviewed-by: Ravindra Lokhande >>>>>>>> Reviewed-by: Jon Hunter >>>>>>> (snip) >>>>>>>> @@ -555,6 +553,13 @@ static int hda_tegra_probe(struct >>>>>>>> platform_device *pdev) >>>>>>>> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 if (!azx_has_pm_runtime(chip)) >>>>>>>> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 pm_runtime_= forbid(hda->dev); >>>>>>>> =C2=A0 +=C2=A0=C2=A0=C2=A0 /* explicit resume if runtime PM is dis= abled */ >>>>>>>> +=C2=A0=C2=A0=C2=A0 if (!pm_runtime_enabled(hda->dev)) { >>>>>>>> +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 err =3D hda_tegra_runt= ime_resume(hda->dev); >>>>>>>> +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 if (err) >>>>>>>> +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2= =A0 goto out_free; >>>>>>>> +=C2=A0=C2=A0=C2=A0 } >>>>>>>> + >>>>>>>> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 schedule_work(&hda->probe_work); >>>>>>> Calling runtime_resume here is really confusing... >>>>>> Why? IMO it is better to have a single handler for resuming the >>>>>> device >>>>>> and so if RPM is not enabled we call the handler directly. This is >>>>>> what >>>>>> we have been advised to do in the past and do in other drivers. >>>>>> See ... >>>>> The point is that we're not "resuming" anything there.=C2=A0 It's in = the >>>>> early probe stage, and the device state is uninitialized, not really >>>>> suspended.=C2=A0 It'd end up with just calling the same helper >>>>> (hda_tegra_enable_clocks()), though. >>>> Yes and you can make the same argument for every driver that calls >>>> pm_runtime_get_sync() during probe to turn on clocks, handle resets, >>>> etc, because at the end of the day the very first call to >>>> pm_runtime_get_sync() invokes the runtime_resume callback, when we hav= e >>>> never been suspended. >>> Although there are some magical pm_runtime_*() in some places, most of >>> such pm_runtime_get_sync() is for the actual runtime PM management (to >>> prevent the runtime suspend), while the code above is for explicitly >>> setting up something for non-PM cases. >>> >>> And if pm_runtime_get_sync() is obviously superfluous, we should >>> remove such calls.=C2=A0 Really. >> Yes agree. >> >>>> Yes at the end of the day it is the same and given that we have done >>>> this elsewhere I think it is good to be consistent if/where we can. >>> The code becomes less readable, and that's a good reason against it :) >> I don't its less readable. However, I do think it is less error prone :-= ) >=20 > Do we have a consensus here? Request others to provide opinions to help > close on this. I am not going to block this and ultimately it is Iwai-san call. However, I wonder if it would be appropriate to move the whole ... if (pm_runtime_enabled()) ret =3D pm_runtime_get_sync(); else ret =3D hda_tegra_runtime_resume(); ... into the probe_work function? In other words, we are just resuming when we really need to. Unless I am still misunderstanding Iwai-san comment. Otherwise if Iwai-san is happy with V2 then go with that. Cheers Jon --=20 nvpublic