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=-17.3 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A, SPF_HELO_NONE,SPF_PASS,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 3773CC433ED for ; Wed, 7 Apr 2021 18:02:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0612B6128D for ; Wed, 7 Apr 2021 18:02:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234479AbhDGSCx (ORCPT ); Wed, 7 Apr 2021 14:02:53 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:31754 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234175AbhDGSCw (ORCPT ); Wed, 7 Apr 2021 14:02:52 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1617818561; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=M7ehjgK6RINiK/yl9HBkU3LoriM4xfDLflETYOr86Gw=; b=eivKU3h4M2ANJCV6HmCNBuJwBj0Hi0u+VAkRSUOzQ7jst+boOTWw/aa5H04wRal5auupi+ oNWWNNgm+oFOEQrNaCr6kHeisWPLig6RaFQ4UAyyKYbUtI0xVdkWiqoFNh9L2NQ1kiwbGs VLGp3bxHBXScmQ1D2DRICqgoKuY2F8E= Received: from mail-ej1-f69.google.com (mail-ej1-f69.google.com [209.85.218.69]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-333-fB7KB7iXP-qTJPWM4WFqww-1; Wed, 07 Apr 2021 14:02:40 -0400 X-MC-Unique: fB7KB7iXP-qTJPWM4WFqww-1 Received: by mail-ej1-f69.google.com with SMTP id v27so7229595ejq.0 for ; Wed, 07 Apr 2021 11:02:40 -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=M7ehjgK6RINiK/yl9HBkU3LoriM4xfDLflETYOr86Gw=; b=UtY9YUSBk7x6CZWFcUowhAitQCHb1kWVlTixaw6Px9BpOvHA0jQTH7xMHDn0iMf85b YYi2a+m3PIoFmoPSGbe5vdOfBuj0GlDNOSaLqTt2maf7Rc7Ld13POkw62fO+Hv9JyvZi hCc7++xq45zSJndUR3dwRBxvGXMABZoakHVHFoh4DgaVmACPdIAkLKWafc143OgUKDFY cUj6wULmpawCkPhvbT5U/MCbN1GI8R83fLrW+CFEK8H8KeN9DLaOgVOa8ezw/ANiJ4b4 WO0Ja7fsw6u7gCplBZyb+Hwj3Ael+m1M1P7wQIBNI+Dq7sPyG1RM43bmejzvm+5zyTNm MBwg== X-Gm-Message-State: AOAM530DhxcZe7ZW7zKndDEhCZtoq1D26AKPLySAEnkHhATOlGj39EBT Xr1O8u28scXiINXHpv/C9kMQAIt0V1R2mxdwY5XjF8Bq2ledstAb3ATX1GDgyRwwDlxUHOwyX3M jW6RTBwpwYT8I6wrsHz6Yv5AiYzSfg8m0BOcifhNyaM2rYe5/RlVRCSbNsCf6MMYL07cDK/sXgg == X-Received: by 2002:a17:906:f9c2:: with SMTP id lj2mr5071029ejb.195.1617818558742; Wed, 07 Apr 2021 11:02:38 -0700 (PDT) X-Google-Smtp-Source: ABdhPJzK725+ILnRkQ4vSs3I2qAt0qEtqKhNqM91f7PqiD8a6kwG8A8HSEm6GE7+u+tEw45FVG0T4g== X-Received: by 2002:a17:906:f9c2:: with SMTP id lj2mr5071006ejb.195.1617818558501; Wed, 07 Apr 2021 11:02:38 -0700 (PDT) Received: from x1.localdomain (2001-1c00-0c1e-bf00-1054-9d19-e0f0-8214.cable.dynamic.v6.ziggo.nl. [2001:1c00:c1e:bf00:1054:9d19:e0f0:8214]) by smtp.gmail.com with ESMTPSA id u13sm7669561ejr.100.2021.04.07.11.02.38 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 07 Apr 2021 11:02:38 -0700 (PDT) Subject: Re: [PATCH 1/2] ACPI: utils: Add acpi_reduced_hardware() helper To: "Rafael J. Wysocki" Cc: "Rafael J . Wysocki" , Len Brown , Zhang Rui , intel-gfx , ACPI Devel Maling List References: <20210406211653.182338-1-hdegoede@redhat.com> <4e796690-0a45-77e9-6b5d-61b3efa4b301@redhat.com> From: Hans de Goede Message-ID: Date: Wed, 7 Apr 2021 20:02:32 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.7.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-acpi@vger.kernel.org Hi, On 4/7/21 7:50 PM, Rafael J. Wysocki wrote: > On Wed, Apr 7, 2021 at 7:43 PM Hans de Goede wrote: >> >> Hi, >> >> On 4/7/21 7:13 PM, Rafael J. Wysocki wrote: >>> On Tue, Apr 6, 2021 at 11:17 PM Hans de Goede wrote: >>>> >>>> Add a getter for the acpi_gbl_reduced_hardware variable so that modules >>>> can check if they are running on an ACPI reduced-hw platform or not. >>>> >>>> Signed-off-by: Hans de Goede >>>> --- >>>> drivers/acpi/utils.c | 11 +++++++++++ >>>> include/acpi/acpi_bus.h | 1 + >>>> include/linux/acpi.h | 5 +++++ >>>> 3 files changed, 17 insertions(+) >>>> >>>> diff --git a/drivers/acpi/utils.c b/drivers/acpi/utils.c >>>> index 682edd913b3b..4cb061d3169a 100644 >>>> --- a/drivers/acpi/utils.c >>>> +++ b/drivers/acpi/utils.c >>>> @@ -872,6 +872,17 @@ acpi_dev_get_first_match_dev(const char *hid, const char *uid, s64 hrv) >>>> } >>>> EXPORT_SYMBOL(acpi_dev_get_first_match_dev); >>>> >>>> +/** >>>> + * acpi_reduced_hardware - Return if this is an ACPI-reduced-hw machine >>>> + * >>>> + * Return true when running on an ACPI-reduced-hw machine, false otherwise. >>>> + */ >>>> +bool acpi_reduced_hardware(void) >>>> +{ >>>> + return acpi_gbl_reduced_hardware; >>>> +} >>>> +EXPORT_SYMBOL(acpi_reduced_hardware); >>> >>> EXPORT_SYMBOL_GPL()? >> >> Yes, that was my intention, no idea what happened here. I just prepped and send out v2 and I think I know what happened, all the other functions in drivers/acpi/utils.c are EXPORT_SYMBOL, so I probably just copy-and-pasted this without too much thinking. It might be worthwhile to see if we should also mark some other functions as EXPORT_SYMBOL_GPL() here. >> Before I send a v2, do you have any remarks on patch 2/2 (which is actually >> the more interesting patch) ? > > I thought that basing that check on the ACPICA's global variable may > be too coarse grained for some cases, but then I've decided to do it > as is now and we'll see. Yes, the whole code for selecting which backlight driver to use is mostly heuristics, so "we'll see" indeed . With that said I'm pretty confident that this change should not cause problems. Platforms which actually set acpi_gbl_reduced_hardware=true seem to be quite rare. I'm actually only aware of Bay Trail-T based devices doing this. Regards, Hans