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 Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 490B4C6FD1F for ; Wed, 22 Mar 2023 08:20:23 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 6AAD910E8A2; Wed, 22 Mar 2023 08:20:09 +0000 (UTC) Received: from EUR05-DB8-obe.outbound.protection.outlook.com (mail-db8eur05on2071.outbound.protection.outlook.com [40.107.20.71]) by gabe.freedesktop.org (Postfix) with ESMTPS id A5A0010E0A2 for ; Wed, 22 Mar 2023 05:13:27 +0000 (UTC) ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=bMvRsPlsK0W8KWfhGFQQQna7R4VOmseqh/vMbwOgVXiYZmQLUE4mGWoOdCYE47xB1gQYwvcehSP8J3CteW5frI2/Dj2fALsib6ogMwtgol9GH6HEVJWfBYriIvqRe5go5oUeQYo6LchyPmwryJQ8nMCLA3EKnsFH3AJBYjcv/mAeDKbIq7cDMnOou6WO0SrkslUh66Vq/F4fk3slhiJF/5qBvSwmU0LYNPKu/iezmuQ236I0ztRzAf4WNWzGb4QzkKFA3s2Ycqa/SPDv8MyUKQ7kB4JSFsmlcB4M/2kOYz6Y74K7ALaHm7Q2jiwRsdQXqpOiXmJdROM9uoWA9qP3sg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector9901; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-AntiSpam-MessageData-ChunkCount:X-MS-Exchange-AntiSpam-MessageData-0:X-MS-Exchange-AntiSpam-MessageData-1; bh=+sldI6X65jjJ+msiJYM4gXqHTuqRYY8LhNwyWxPOOyc=; b=Ou721I1VO7xJimXZGQxsBRlqHNwXvvjVhcZXCvTTIQjrKuioYFS1GG5HT0DF4nTHv/8Ag1wjG/xJtoE4vmDcX+YknWQYGl2CIh59eL1ZX3g4bdpFBcNZo+hEJLwOrt6RrgQv7q5q1lj1gTKSGP3C30m9quZBlpYDvwJtDC/3O5jdk0t3X7Qt23p3JaDPxF8WQof9x/uYfvo4to4BS5rvTVnNNtA6783kiIUardoLH0IPF7ftd/AA/QOW/3y4zb1dOXzc6O6fxJ8psIzL+sAqlhftmKkv7ESsRDPCAoGSUvfbbQEOqmQsDoR8nbY0+T5Xc09ekkYDTf9EwpkaWZK+jg== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=nxp.com; dmarc=pass action=none header.from=nxp.com; dkim=pass header.d=nxp.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nxp.com; s=selector2; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=+sldI6X65jjJ+msiJYM4gXqHTuqRYY8LhNwyWxPOOyc=; b=q1b5Jk7JbN3DGrbELd7+bK72rBRTFGGqo7e6tcRPZLqh2H2dQ6mv7sO21sdxijXotOKt9S7/0ai9D7Na+wPssOL6+HLFHNjakj0trjYbJo41A06oLn/LmuIUmNYOlbYKplt4XIudIS+WOpBEmYRk91X0hpf4PqqdkMWMN6OYkwM= Received: from DB9PR04MB8477.eurprd04.prod.outlook.com (2603:10a6:10:2c3::11) by PA4PR04MB9591.eurprd04.prod.outlook.com (2603:10a6:102:270::18) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.6178.37; Wed, 22 Mar 2023 05:13:24 +0000 Received: from DB9PR04MB8477.eurprd04.prod.outlook.com ([fe80::3d8f:f805:bf35:b33]) by DB9PR04MB8477.eurprd04.prod.outlook.com ([fe80::3d8f:f805:bf35:b33%4]) with mapi id 15.20.6178.037; Wed, 22 Mar 2023 05:13:24 +0000 From: Aisheng Dong To: "u.kleine-koenig@pengutronix.de" Subject: Re: [PATCH v2 1/2] backlight: pwm_bl: Configure pwm only once per backlight toggle Thread-Topic: Re: [PATCH v2 1/2] backlight: pwm_bl: Configure pwm only once per backlight toggle Thread-Index: Adlcb4jabv+aAJvFTvysosjUWHNaHw== Date: Wed, 22 Mar 2023 05:13:24 +0000 Message-ID: Accept-Language: zh-CN, en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: authentication-results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=nxp.com; x-ms-publictraffictype: Email x-ms-traffictypediagnostic: DB9PR04MB8477:EE_|PA4PR04MB9591:EE_ x-ms-office365-filtering-correlation-id: c0b0e1fb-c091-43a2-8bdb-08db2a94296b x-ms-exchange-senderadcheck: 1 x-ms-exchange-antispam-relay: 0 x-microsoft-antispam: BCL:0; x-microsoft-antispam-message-info: 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 x-forefront-antispam-report: CIP:255.255.255.255; CTRY:; LANG:en; SCL:1; SRV:; IPV:NLI; SFV:NSPM; H:DB9PR04MB8477.eurprd04.prod.outlook.com; PTR:; CAT:NONE; SFS:(13230025)(4636009)(376002)(366004)(136003)(346002)(39860400002)(396003)(451199018)(186003)(38100700002)(9686003)(122000001)(2906002)(26005)(44832011)(6506007)(38070700005)(7416002)(5660300002)(52536014)(8676002)(8936002)(66476007)(86362001)(66946007)(76116006)(66556008)(64756008)(55016003)(7696005)(66574015)(41300700001)(33656002)(66446008)(6916009)(4326008)(83380400001)(54906003)(71200400001)(478600001)(316002); DIR:OUT; SFP:1101; x-ms-exchange-antispam-messagedata-chunkcount: 1 x-ms-exchange-antispam-messagedata-0: =?iso-8859-1?Q?2LWWLOs6EgeAjvnQo2nGh3ZGARfjdy72UFKcxo9zUUwczRnF3Wv13AS48B?= =?iso-8859-1?Q?SoWEHYSShc5LoeRE7f1Xpp+9hefTJTN2cActda793wh14x9HjgUyPgByWQ?= =?iso-8859-1?Q?pPQGe+1o6FP8tW16n9QlbfYIjDVGtoMlN1ypt8/8kqUtQvULAnSgOIz7iz?= =?iso-8859-1?Q?P1vmTZSYUCImasIpwJRxv+fL2xcy2tbDRMnQJmilEwWjOg4tDdNqY1FeGd?= =?iso-8859-1?Q?0O700WbEU3iQsTaTb4hgc3O4RanF9wPkT4xn5c1jmzG/AFk4TFruz1PYtg?= =?iso-8859-1?Q?SoeJ50HXCZMcS6hsQCo3EWtzAlOX00YixYOORw3T2VJMlaRncqKBY1B9P7?= =?iso-8859-1?Q?GGYhQuOtvFN9FRHWX8qx7wNA0jr1kNOuJdra2u7e9ge3QcsdgFyxzsGbLQ?= =?iso-8859-1?Q?SOjOVVux1+Bg3hx/6SGTCb1/ZmHzlLX/Af7c54z2DJQYkhUJ0CrVW+Q8Bi?= =?iso-8859-1?Q?R4OcF4A6diZrxOQ+S3G2YcVRgcvyFuGBR87ksNpxz8pbzG/QyT/tj+ilEa?= =?iso-8859-1?Q?cBGTh+kiPvke4zkLD76XcKBjTRmyyHqOnYXtlZfk3/6uCdhMEhrRNzbx/b?= =?iso-8859-1?Q?HhWH4aDocSjvq+ig0Z5PP8W/4d0VJ//SI+fhHkjXtgNzXztgZVEiKh3yR1?= =?iso-8859-1?Q?R6TPd1xJYW3G9tB4mvhv+n1f48a+VhlaWdVa6KzHYKVy+VAKpCtNQNp+iC?= =?iso-8859-1?Q?Ns9Y2zYqOywUGoBDga9TW0WgsO/fxKgFUinQK/zvSi98aQnl8rsmXfzfSq?= =?iso-8859-1?Q?ezSDFjOQI/EfGyOrt3E9mFr09enKGyikmf1BufAl/R8pHreT6m6Y0I384v?= =?iso-8859-1?Q?0RL+erEZjTek1xJXdMWVgawsk+BamJuuvJHgMEIwfNOwwIHlGs+zVdgizN?= =?iso-8859-1?Q?oSoHjG+L8q5h2ytxpz2i12Xm2Vt925gcp4poWBq+z9XRnaC+XM2SUsoCP3?= =?iso-8859-1?Q?UU5OfWUJCR4IgM5Doq887zDrFKraHXQfXS61YUZTtc6RMLMzEuCu0Q02b9?= =?iso-8859-1?Q?FIVHjF5E9QMKzsJqrb1IyfpAd5xxWFdOR5rh9CpjZyYZbdFh1qIxBIizDl?= =?iso-8859-1?Q?o2kvNBYBNEKgBdU7HhppHOdufK7H7STjjL4qipeP+HvYb/nIVG2UYokwFH?= =?iso-8859-1?Q?vsjSlxqiJXdkldIkVmmXAzu9Nj3g1nECl6b3HDHf7Kp7anZ30Dnn24X0a2?= =?iso-8859-1?Q?wfugBA5y23ckFyDc9dx8yIx8wCcuZWWp0flqdIDY4STim4z18jL6aFocyc?= =?iso-8859-1?Q?W55ebJBgIPRg/YUmkcF6CJrk5yp1mL62Lx3Y5OLC+9rmCiLRxCvfvp1pT/?= =?iso-8859-1?Q?M7vrmaMf30Wsj9t/0SSuWKIum3r8bZnFeiy+cipTf324wYrVCnWn3/LfGL?= =?iso-8859-1?Q?dSTSmTA4/IlxNt9MhypYlnFcCrraXLeOD4q/1e7kUE89VgfqoRIItB3zX8?= =?iso-8859-1?Q?9vleQ2hHid/hynZkMq9gVhmTDAD0oBwJwVQa2llHxtj1A610m348KGWKh2?= =?iso-8859-1?Q?Bazs83NoW0Gti6CFRpbHlksMEGnhP9HFVJhJfL/sqSYy3lhXZMSrf0uayr?= =?iso-8859-1?Q?crB4gfyJx7vK27AftbMlXrVF8SbMhY4wr2ltpHWHUQLXuFMUZH26f9OLdj?= =?iso-8859-1?Q?db4ihyq9R6B8Z8/GtGTfUNhsIYtbYa1SWY?= Content-Type: multipart/alternative; boundary="_000_DB9PR04MB84779AF9758B7FE747C6693D80869DB9PR04MB8477eurp_" MIME-Version: 1.0 X-OriginatorOrg: nxp.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-AuthSource: DB9PR04MB8477.eurprd04.prod.outlook.com X-MS-Exchange-CrossTenant-Network-Message-Id: c0b0e1fb-c091-43a2-8bdb-08db2a94296b X-MS-Exchange-CrossTenant-originalarrivaltime: 22 Mar 2023 05:13:24.1341 (UTC) X-MS-Exchange-CrossTenant-fromentityheader: Hosted X-MS-Exchange-CrossTenant-id: 686ea1d3-bc2b-4c6f-a92c-d99c5c301635 X-MS-Exchange-CrossTenant-mailboxtype: HOSTED X-MS-Exchange-CrossTenant-userprincipalname: aCaOLpR+nIeXg2m+uMZnKwylzmzwDdpa+QDgdSDLx2XXuFKmg/SO1RitLrPtETp4NddtXAfTuDeuQigSAZDFPw== X-MS-Exchange-Transport-CrossTenantHeadersStamped: PA4PR04MB9591 X-Mailman-Approved-At: Wed, 22 Mar 2023 08:20:06 +0000 X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: "daniel.thompson@linaro.org" , "linux-pm@vger.kernel.org" , Jingoo Han , "deller@gmx.de" , "lee@kernel.org" , "linux-fbdev@vger.kernel.org" , "dri-devel@lists.freedesktop.org" , "thierry.reding@gmail.com" , "kernel@pengutronix.de" Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" --_000_DB9PR04MB84779AF9758B7FE747C6693D80869DB9PR04MB8477eurp_ Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable On Fri, Jan 20, 2023 at 01:00:18PM +0100, Uwe Kleine-K=F6nig wrote: > Most but not all PWMs drive the PWM pin to its inactive state when > disabled. However if there is no enable_gpio and no regulator the PWM > must drive the inactive state to actually disable the backlight. > > So keep the PWM on in this case. > > Note that to determine if there is a regulator some effort is required > because it might happen that there isn't actually one but the regulator > core gave us a dummy. (A nice side effect is that this makes the > regulator actually optional even on fully constrained systems.) > > This fixes backlight disabling e.g. on i.MX6 when an inverted PWM is > used. > > Hint for the future: If this change results in a regression, the bug is > in the lowlevel PWM driver. > Signed-off-by: Uwe Kleine-K=F6nig u.kleine-koenig@pengutronix.de This patch broke imx7ulp suspend resume and got the following error: Freezing remaining freezable tasks Freezing remaining freezable tasks completed (elapsed 0.001 seconds) printk: Suspending console(s) (use no_console_suspend to debug) asix 1-1:1.0 eth0: Link is Down imx7ulp-tpm-pwm 40250000.pwm: PM: dpm_run_callback(): platform_pm_suspend+0= x0/0x48 returns -16 imx7ulp-tpm-pwm 40250000.pwm: PM: failed to suspend: error -16 ... It seems this patch changed the behavior of pwm_backlight_suspend a little = bit in pwm_backlight_power_off() that pwm state keep unchanged during suspend. Then pwm_imx_tpm_suspend() will return -Ebusy due to tpm->enable_count > 0. Was this intended behavior? Should we fix pwm core or the driver? Regards Aisheng --_000_DB9PR04MB84779AF9758B7FE747C6693D80869DB9PR04MB8477eurp_ Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable

On Fri, Jan 20, 2023 at 01:00:1= 8PM +0100, Uwe Kleine-K=F6nig wrote:

> Most but not all PWMs driv= e the PWM pin to its inactive state when

> disabled. However if there= is no enable_gpio and no regulator the PWM

> must drive the inactive st= ate to actually disable the backlight.

> 

> So keep the PWM on in this= case.

> 

> Note that to determine if = there is a regulator some effort is required

> because it might happen th= at there isn't actually one but the regulator

> core gave us a dummy. (A n= ice side effect is that this makes the

> regulator actually optiona= l even on fully constrained systems.)

> 

> This fixes backlight disab= ling e.g. on i.MX6 when an inverted PWM is

> used.

> 

> Hint for the future: If th= is change results in a regression, the bug is

> in the lowlevel PWM driver= .

> Signed-off-by: Uwe Kleine-= K=F6nig u.kleine-koenig@pengutronix.de

 

This patch broke imx7ulp suspen= d resume and got the following error:

Freezing remaining freezable ta= sks

Freezing remaining freezable ta= sks completed (elapsed 0.001 seconds)

printk: Suspending console(s) (= use no_console_suspend to debug)

asix 1-1:1.0 eth0: Link is Down=

imx7ulp-tpm-pwm 40250000.pwm: P= M: dpm_run_callback(): platform_pm_suspend+0x0/0x48 returns -16<= /span>

imx7ulp-tpm-pwm 40250000.pwm: P= M: failed to suspend: error -16

…

 

It seems this patch changed the= behavior of pwm_backlight_suspend a little bit in

pwm_backlight_power_off() that = pwm state keep unchanged during suspend.

Then pwm_imx_tpm_suspend() will= return -Ebusy due to tpm->enable_count > 0.

Was this intended behavior? Sho= uld we fix pwm core or the driver?

 

Regards

Aisheng

--_000_DB9PR04MB84779AF9758B7FE747C6693D80869DB9PR04MB8477eurp_--