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=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 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 81A16C433FF for ; Thu, 8 Aug 2019 10:19:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 57F39217D7 for ; Thu, 8 Aug 2019 10:19:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389792AbfHHKT5 (ORCPT ); Thu, 8 Aug 2019 06:19:57 -0400 Received: from mail-ed1-f67.google.com ([209.85.208.67]:38910 "EHLO mail-ed1-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389773AbfHHKT4 (ORCPT ); Thu, 8 Aug 2019 06:19:56 -0400 Received: by mail-ed1-f67.google.com with SMTP id r12so55348829edo.5 for ; Thu, 08 Aug 2019 03:19:55 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=oS2cy/4g4RlDFRc+61zq/UgTVPK/pNrXepKdT+yLXco=; b=r4/T8RbiIabn+Yb30jNOkoPAoEcFC1K/SGzal0BXIcjE6E04p3gKxfUPYYlbb+xaxo ADBDXxVi5fMdcdwYZQDc8L/Ae6MNperIHZ1hDtBz81mvxCtedKXzzvzgOsq/7eUNrzoS M1ZRc4K/rruc1lUCgH/D/WA7jWuCoPsrjMkFyKGooqNAaCATPlxa5zZDKfNHAkfBybg7 ryQWN1YrNTFPIOMa2wB9Zj1Zwrkf+Tvk/kkSvUGZsONwOUXstJiALIU0r9NlUZYfX3hV jUQAOgnlg7DGt+bxfZH6qY+eoYS3QeExu1VvWli631rkm3rT/w4V/u6baOrOxI4XBKft pRxA== X-Gm-Message-State: APjAAAX7BitabL1pBtUKqvnskYzokIZLRy1yRHBUXxX1QyaxTh1klJwh gdNoo1LJQnirnVEYAug8aKD+1Q== X-Google-Smtp-Source: APXvYqw2tM5paSc8isBKnWGgAwEZzKYdgftiYWcXUtMBKQI/XSRFBC0NiTak9ef5A70MD36m5r7g2Q== X-Received: by 2002:a17:906:e204:: with SMTP id gf4mr12251166ejb.302.1565259594667; Thu, 08 Aug 2019 03:19:54 -0700 (PDT) Received: from shalem.localdomain (84-106-84-65.cable.dynamic.v4.ziggo.nl. [84.106.84.65]) by smtp.gmail.com with ESMTPSA id b30sm22057756ede.88.2019.08.08.03.19.53 (version=TLS1_3 cipher=AEAD-AES128-GCM-SHA256 bits=128/128); Thu, 08 Aug 2019 03:19:53 -0700 (PDT) Subject: Re: [PATCH 5.3 regression fix] pwm: Fallback to the static lookup-list when acpi_pwm_get fails To: Thierry Reding Cc: Andy Shevchenko , linux-pwm@vger.kernel.org, linux-acpi@vger.kernel.org, youling257@gmail.com, Nikolaus Voss References: <20190730154848.5164-1-hdegoede@redhat.com> From: Hans de Goede Message-ID: <31c3f15e-649e-a3c1-56e2-0c35fda24ae1@redhat.com> Date: Thu, 8 Aug 2019 12:19:53 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: <20190730154848.5164-1-hdegoede@redhat.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-acpi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-acpi@vger.kernel.org Thierry, Ping? This fixes a somewhat serious regression in 5.3, can we please get this queued up for merging into 5.3 ? Regards, Hans On 30-07-19 17:48, Hans de Goede wrote: > Commit 4a6ef8e37c4d ("pwm: Add support referencing PWMs from ACPI") > made pwm_get unconditionally return the acpi_pwm_get return value if > the device passed to pwm_get has an ACPI fwnode.Thieer > > But even if the passed in device has an ACPI fwnode, it does not > necessarily have the necessary ACPI package defining its pwm bindings, > especially since the binding / API of this ACPI package has only been > introduced very recently. > > Up until now X86/ACPI devices which use a separate pwm controller for > controlling their LCD screen's backlight brightness have been relying > on the static lookup-list to get their pwm. > > pwm_get unconditionally returning the acpi_pwm_get return value breaks > this, breaking backlight control on these devices. > > This commit fixes this by making pwm_get fall back to the static > lookup-list if acpi_pwm_get returns -ENOENT. > > BugLink: https://bugs.freedesktop.org/show_bug.cgi?id=96571 > Reported-by: youling257@gmail.com > Fixes: 4a6ef8e37c4d ("pwm: Add support referencing PWMs from ACPI") > Cc: Nikolaus Voss > Signed-off-by: Hans de Goede > --- > drivers/pwm/core.c | 7 +++++-- > 1 file changed, 5 insertions(+), 2 deletions(-) > > diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c > index c3ab07ab31a9..8edfac17364e 100644 > --- a/drivers/pwm/core.c > +++ b/drivers/pwm/core.c > @@ -882,8 +882,11 @@ struct pwm_device *pwm_get(struct device *dev, const char *con_id) > return of_pwm_get(dev, dev->of_node, con_id); > > /* then lookup via ACPI */ > - if (dev && is_acpi_node(dev->fwnode)) > - return acpi_pwm_get(dev->fwnode); > + if (dev && is_acpi_node(dev->fwnode)) { > + pwm = acpi_pwm_get(dev->fwnode); > + if (!IS_ERR(pwm) || PTR_ERR(pwm) != -ENOENT) > + return pwm; > + } > > /* > * We look up the provider in the static table typically provided by >