From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jon Hunter Subject: Re: [PATCH] ALSA: hda/tegra: enable clock during probe Date: Fri, 25 Jan 2019 13:26:27 +0000 Message-ID: References: <1548351403-1875-1-git-send-email-spujar@nvidia.com> <06c00ce1-32ed-8aa9-0340-d00202a8fa62@nvidia.com> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org To: Takashi Iwai Cc: Sameer Pujar , pierre-louis.bossart@linux.intel.com, perex@perex.cz, alsa-devel@alsa-project.org, thierry.reding@gmail.com, rlokhande@nvidia.com, linux-kernel@vger.kernel.org, linux-tegra@vger.kernel.org List-Id: linux-tegra@vger.kernel.org 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, >>>> * return code check for pm_runtime_get_sync() to take care of failure >>>> and exit gracefully. >>>> * In remove path runtime PM is disabled before calling snd_card_free(). >>>> * hda_tegra_disable_clocks() is moved out of CONFIG_PM_SLEEP check. >>>> * 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) >>>> if (!azx_has_pm_runtime(chip)) >>>> pm_runtime_forbid(hda->dev); >>>> >>>> + /* explicit resume if runtime PM is disabled */ >>>> + if (!pm_runtime_enabled(hda->dev)) { >>>> + err = hda_tegra_runtime_resume(hda->dev); >>>> + if (err) >>>> + goto out_free; >>>> + } >>>> + >>>> 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. It's in the > early probe stage, and the device state is uninitialized, not really > suspended. 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. 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. Furthermore, there are other various drivers in the kernel that do the same ... drivers/i2c/busses/i2c-img-scb.c drivers/dma/xilinx/zynqmp_dma.c drivers/gpu/drm/arm/malidp_drv.c Cheers Jon -- nvpublic 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=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 84106C282C0 for ; Fri, 25 Jan 2019 13:26:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 54883218D0 for ; Fri, 25 Jan 2019 13:26:34 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=nvidia.com header.i=@nvidia.com header.b="H91ePaCn" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727721AbfAYN0c (ORCPT ); Fri, 25 Jan 2019 08:26:32 -0500 Received: from hqemgate14.nvidia.com ([216.228.121.143]:2912 "EHLO hqemgate14.nvidia.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726095AbfAYN0c (ORCPT ); Fri, 25 Jan 2019 08:26:32 -0500 Received: from hqpgpgate101.nvidia.com (Not Verified[216.228.121.13]) by hqemgate14.nvidia.com (using TLS: TLSv1.2, DES-CBC3-SHA) id ; Fri, 25 Jan 2019 05:26:30 -0800 Received: from hqmail.nvidia.com ([172.20.161.6]) by hqpgpgate101.nvidia.com (PGP Universal service); Fri, 25 Jan 2019 05:26:31 -0800 X-PGP-Universal: processed; by hqpgpgate101.nvidia.com on Fri, 25 Jan 2019 05:26:31 -0800 Received: from [10.21.132.148] (172.20.13.39) by HQMAIL101.nvidia.com (172.20.187.10) with Microsoft SMTP Server (TLS) id 15.0.1395.4; Fri, 25 Jan 2019 13:26:29 +0000 Subject: Re: [PATCH] ALSA: hda/tegra: enable clock during probe To: Takashi Iwai CC: Sameer Pujar , , , , , , , References: <1548351403-1875-1-git-send-email-spujar@nvidia.com> <06c00ce1-32ed-8aa9-0340-d00202a8fa62@nvidia.com> From: Jon Hunter Message-ID: Date: Fri, 25 Jan 2019 13:26:27 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.2.1 MIME-Version: 1.0 In-Reply-To: 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: 7bit DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nvidia.com; s=n1; t=1548422790; bh=PFxm0QupoaG7oKh+/xHrIXcLL7nFXDBr4VQJxJePcyQ=; 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=H91ePaCntofN3RWAb0zxLhM3QjxIjNW6395c12fSnxyOkp4t93bQDlSiaURrLheR2 cmWL10c3twLfxy+GOeb70S8MTFGH63Xtig6nFcpF3jKt+tbvElmLzXv4370dZhGDHp RaIJaoe7VICZXTSJisWxyPDGKVN6w3OP3VJOPBJ57uANBg4tRpBLgajUXw4QND97Cl yhyZkebXrA4ziph8vWv12IE4S0WOxlxjyM1rmSi8qcqIX0co3YBUZt1TvKK/HEA6ww MuvWIe5//bUKPhto0I9sRnxk+AU9dYe0QTn6h/mn2mL80ZPEFjzglOLn49GhY+ZGf2 cRjnh51CPDIBg== Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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, >>>> * return code check for pm_runtime_get_sync() to take care of failure >>>> and exit gracefully. >>>> * In remove path runtime PM is disabled before calling snd_card_free(). >>>> * hda_tegra_disable_clocks() is moved out of CONFIG_PM_SLEEP check. >>>> * 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) >>>> if (!azx_has_pm_runtime(chip)) >>>> pm_runtime_forbid(hda->dev); >>>> >>>> + /* explicit resume if runtime PM is disabled */ >>>> + if (!pm_runtime_enabled(hda->dev)) { >>>> + err = hda_tegra_runtime_resume(hda->dev); >>>> + if (err) >>>> + goto out_free; >>>> + } >>>> + >>>> 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. It's in the > early probe stage, and the device state is uninitialized, not really > suspended. 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. 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. Furthermore, there are other various drivers in the kernel that do the same ... drivers/i2c/busses/i2c-img-scb.c drivers/dma/xilinx/zynqmp_dma.c drivers/gpu/drm/arm/malidp_drv.c Cheers Jon -- nvpublic