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 1A79BC282D8 for ; Wed, 30 Jan 2019 12:24:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D6DD12175B for ; Wed, 30 Jan 2019 12:24:31 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=nvidia.com header.i=@nvidia.com header.b="mBEYDenT" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730083AbfA3MYa (ORCPT ); Wed, 30 Jan 2019 07:24:30 -0500 Received: from hqemgate14.nvidia.com ([216.228.121.143]:19573 "EHLO hqemgate14.nvidia.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725768AbfA3MY3 (ORCPT ); Wed, 30 Jan 2019 07:24:29 -0500 Received: from hqpgpgate101.nvidia.com (Not Verified[216.228.121.13]) by hqemgate14.nvidia.com (using TLS: TLSv1.2, DES-CBC3-SHA) id ; Wed, 30 Jan 2019 04:24:28 -0800 Received: from hqmail.nvidia.com ([172.20.161.6]) by hqpgpgate101.nvidia.com (PGP Universal service); Wed, 30 Jan 2019 04:24:26 -0800 X-PGP-Universal: processed; by hqpgpgate101.nvidia.com on Wed, 30 Jan 2019 04:24:26 -0800 Received: from [10.26.11.176] (172.20.13.39) by HQMAIL101.nvidia.com (172.20.187.10) with Microsoft SMTP Server (TLS) id 15.0.1395.4; Wed, 30 Jan 2019 12:24:20 +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>

<4aee601a-f72c-7c94-60cb-ec2546900b8c@nvidia.com> From: Jon Hunter Message-ID: <4a607da0-616b-378d-b62a-598277f0254c@nvidia.com> Date: Wed, 30 Jan 2019 12:24:17 +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: <4aee601a-f72c-7c94-60cb-ec2546900b8c@nvidia.com> X-Originating-IP: [172.20.13.39] X-ClientProxiedBy: HQMAIL103.nvidia.com (172.20.187.11) 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=1548851068; bh=Dv3izO7JVnkQTWXiJQwOVanSyC6UNsmqZDc4KyzEQrI=; 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=mBEYDenTKJ2HMPUkIr2MGdTr/9AOeiKTC7rFgIbPod0M/WoeYvwcJqK+30oLWmM8H yAA/+zjqJh5hUPTYpe8Z5hrMIOsX2r81XLj6RV5Wisabpe4Bz26HOgnokjun0iBi26 O2PoKhVmnPUrNbgh9o/JWDU6nn4Qj+Yr183Ri1P23dxn+v3InvAhQm8IsQrUdk7UiM sASHNVjp8A06zqpWaY+gmO4nUf3iVQRcZW7QNGivsaOF2Lv+DCNkVYdbbE6EoMzL0s x7Ow4sspFilObpMFc/hLZDcKqgt1KBws9RipjjPGFbSJUKQNF1cIvlijY70kgHKd0W rwr9DCyjGxB3A== Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 30/01/2019 10:56, Sameer Pujar wrote: >=20 > On 1/30/2019 4:09 PM, Takashi Iwai wrote: >> On Wed, 30 Jan 2019 10:35:35 +0100, >> Jon Hunter wrote: >>> >>> On 28/01/2019 06:06, Sameer Pujar wrote: >>>> 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 init >>>>>>>>>>> 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=C2=A0 * return code check for pm_runtime_get_sync(= ) to take >>>>>>>>>>> care of >>>>>>>>>>> failure >>>>>>>>>>> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 and exit gracefully. >>>>>>>>>>> =C2=A0=C2=A0=C2=A0 * In remove path runtime PM is disabled befo= re calling >>>>>>>>>>> snd_card_free(). >>>>>>>>>>> =C2=A0=C2=A0=C2=A0 * hda_tegra_disable_clocks() is moved out of= CONFIG_PM_SLEEP >>>>>>>>>>> check. >>>>>>>>>>> =C2=A0=C2=A0=C2=A0 * runtime PM callbacks moved out of CONFIG_P= M 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=C2=A0 if (!azx_has_pm_runtime(ch= ip)) >>>>>>>>>>> =C2=A0=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=C2=A0 /* explicit resume if runtime = PM is disabled */ >>>>>>>>>>> +=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_r= untime_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=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 i= s >>>>>>>>> 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 have >>>>>>> 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 don= e >>>>>>> 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 :-) >>>> Do we have a consensus here? Request others to provide opinions to hel= p >>>> 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 ... >>> >>> =C2=A0 if (pm_runtime_enabled()) >>> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 ret =3D pm_runti= me_get_sync(); >>> =C2=A0 else >>> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 ret =3D hda_tegr= a_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. >> Only from my personal taste, I find the v2 patch is better. >> It like simpler, after all.=C2=A0 That is, the code in v1 patch >> >> =C2=A0=C2=A0=C2=A0=C2=A0probe() { >> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 .... >> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 pm_runtime_enable(); >> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 .... >> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 if (!pm_runtime_enabled()) >> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 hda_t= egra_runtime_resume(); >> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 schedule_work(); >> =C2=A0=C2=A0=C2=A0=C2=A0} >> >> =C2=A0=C2=A0=C2=A0=C2=A0work() { >> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 pm_runtime_get_sync(); >> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 .... >> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 pm_runtime_put(); >> =C2=A0=C2=A0=C2=A0=C2=A0} >> >> becomes shorter in v2: >> >> =C2=A0=C2=A0=C2=A0=C2=A0probe() { >> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 .... >> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 hda_tegra_enable_clocks(); >> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 schedule_work(); >> =C2=A0=C2=A0=C2=A0=C2=A0} >> >> =C2=A0=C2=A0=C2=A0=C2=A0work() { >> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 .... >> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 pm_runtime_enable(); >> =C2=A0=C2=A0=C2=A0=C2=A0} >> >> >> However, the point about hda_tegra_remove() you raised in the v2 patch >> is still valid.=C2=A0 (BTW, I guess the discussion followed in that thre= ad >> was somehow misunderstood; your argument was about hda_tegra_remove() >> while Sameer discussed about the probe.)=C2=A0 It can be with >> hda_tegra_disable_clocks() if we want more consistency. >> >> Though, I don't mind too much about that as long as the proper comment >> is given. > We might need entire functionality of hda_tegra_runtime_suspend() > replicated here, > if hda_tegra_disable_clocks() were to be used. Right now it takes care > of both the > cases where runtime PM is enabled/disabled. If you all agree, we can > move the > discussion to v2 patch. We should avoid replicating the function. Jon --=20 nvpublic