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=-4.3 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 E81E4C433E0 for ; Thu, 21 Jan 2021 21:07:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A3B3B23A53 for ; Thu, 21 Jan 2021 21:07:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727437AbhAUVHM (ORCPT ); Thu, 21 Jan 2021 16:07:12 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53610 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726530AbhAUVGt (ORCPT ); Thu, 21 Jan 2021 16:06:49 -0500 Received: from mail-wr1-x42e.google.com (mail-wr1-x42e.google.com [IPv6:2a00:1450:4864:20::42e]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D8C34C0613D6; Thu, 21 Jan 2021 13:06:08 -0800 (PST) Received: by mail-wr1-x42e.google.com with SMTP id q7so3081583wre.13; Thu, 21 Jan 2021 13:06:08 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-transfer-encoding:content-language; bh=c32MJxHbMXKIzSN7o1VmWc7TXb9b5e1CGXL5LOjwT6g=; b=u4djjoC9hSNDXFyCd/ImL8m1DEWuw8KUuPgFO4phIYc7TOTB4CPy+dLgKxjevXx5mT aMDyGnjPAbpkNoz0XiEu1zkYimth4y6ArIV6H2SfbowC+6byq4OvFu5Wb8irSEEPzC5s ChEql7/rDpn97TdjI8DAiFkTWaMWOfkSeQyAI70Tfm2EoN8crnvZiL0IiayzLCm45GjT ki+OV8OG6dB1C/BZCYmEhG3ve23znznRaL3Sc7a4LKQDcXH+mgJaC8/DKhFeB/GJICM3 OtAquWWmeL0gjKWo6uNRBPgh17Qm9UVJBPq8mPuXHWCMrZwOY4OvyN0gA/Krbv0V7TJ+ XvGw== 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-transfer-encoding :content-language; bh=c32MJxHbMXKIzSN7o1VmWc7TXb9b5e1CGXL5LOjwT6g=; b=g1NQiNlZiJlRRMxj93JRs0N5hd+NtSqYKxF5OOZ8UEUb4Z48tPfFaxUG9o0sRdijGa r11XhPAZOP9NhXtakUDGtB7vqlS8A/L7362IyaxD+Zz/JsCT1vJm6ihhT6J41h0lLVwl KSRNe2XD6o18nIA+gmTiKK9T3a4V0YVLHH7xdSdaBnZC7muJngD0OuX8JYTYAfeGiv32 mxFNOXA6u+7CN3s0dV6v9SdSGe1Phhb0s3Pd4zGRpBVSFpoX+QTTQ1sbt1Xf6pbL+JNL 5KTLh5ZCYk6x68fK3viEzqn7ijBuFGyIw2x9IaolBgTAEfp0he7y6azesP2t4SGQiHE7 2F3w== X-Gm-Message-State: AOAM532Fp5ElwFkaJlPEhv6LGoZECY0OKyHj/ILLMdfRBpAHYJlxzpOx ps4vA/iX4dveTB+hALo6e/U= X-Google-Smtp-Source: ABdhPJyvMM67co17b2bl8bFHYOAqV+64lTyRfq/UMtWF4DXtiVki1RKalX7zaoMBeipjrKk8oZCZwg== X-Received: by 2002:adf:ba49:: with SMTP id t9mr1251120wrg.183.1611263167561; Thu, 21 Jan 2021 13:06:07 -0800 (PST) Received: from [192.168.1.211] ([2.29.208.120]) by smtp.gmail.com with ESMTPSA id a130sm9049021wmf.4.2021.01.21.13.06.06 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 21 Jan 2021 13:06:06 -0800 (PST) Subject: Re: [PATCH v2 2/7] acpi: utils: Add function to fetch dependent acpi_devices To: "Rafael J. Wysocki" Cc: Linux Kernel Mailing List , ACPI Devel Maling List , linux-gpio@vger.kernel.org, linux-i2c , Platform Driver , "open list:ACPI COMPONENT ARCHITECTURE (ACPICA)" , "Rafael J. Wysocki" , Len Brown , andy@kernel.org, Mika Westerberg , Linus Walleij , Bartosz Golaszewski , Wolfram Sang , Lee Jones , Hans de Goede , Mark Gross , Robert Moore , Erik Kaneda , Sakari Ailus , Andy Shevchenko , Laurent Pinchart , Kieran Bingham References: <20210118003428.568892-1-djrscally@gmail.com> <20210118003428.568892-3-djrscally@gmail.com> <85ccf00d-7c04-b1da-a4bc-82c805df69c9@gmail.com> <0fac24d2-e8fc-7dc8-0f2f-44c7aadb1daf@gmail.com> From: Daniel Scally Message-ID: Date: Thu, 21 Jan 2021 21:06:05 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Content-Language: en-US Precedence: bulk List-ID: X-Mailing-List: linux-acpi@vger.kernel.org On 21/01/2021 18:08, Rafael J. Wysocki wrote: > On Thu, Jan 21, 2021 at 5:34 PM Daniel Scally wrote: >> >> On 21/01/2021 14:39, Rafael J. Wysocki wrote: >>> On Thu, Jan 21, 2021 at 1:04 PM Daniel Scally wrote: >>>> On 21/01/2021 11:58, Rafael J. Wysocki wrote: >>>>> On Thu, Jan 21, 2021 at 10:47 AM Daniel Scally wrote: >>>>>> Hi Rafael >>>>>> >>>>>> On 19/01/2021 13:15, Rafael J. Wysocki wrote: >>>>>>> On Mon, Jan 18, 2021 at 9:51 PM Daniel Scally wrote: >>>>>>>> On 18/01/2021 16:14, Rafael J. Wysocki wrote: >>>>>>>>> On Mon, Jan 18, 2021 at 1:37 AM Daniel Scally wrote: >>>>>>>>>> In some ACPI tables we encounter, devices use the _DEP method to assert >>>>>>>>>> a dependence on other ACPI devices as opposed to the OpRegions that the >>>>>>>>>> specification intends. We need to be able to find those devices "from" >>>>>>>>>> the dependee, so add a function to parse all ACPI Devices and check if >>>>>>>>>> the include the handle of the dependee device in their _DEP buffer. >>>>>>>>> What exactly do you need this for? >>>>>>>> So, in our DSDT we have devices with _HID INT3472, plus sensors which >>>>>>>> refer to those INT3472's in their _DEP method. The driver binds to the >>>>>>>> INT3472 device, we need to find the sensors dependent on them. >>>>>>>> >>>>>>> Well, this is an interesting concept. :-) >>>>>>> >>>>>>> Why does _DEP need to be used for that? Isn't there any other way to >>>>>>> look up the dependent sensors? >>>>>>> >>>>>>>>> Would it be practical to look up the suppliers in acpi_dep_list instead? >>>>>>>>> >>>>>>>>> Note that supplier drivers may remove entries from there, but does >>>>>>>>> that matter for your use case? >>>>>>>> Ah - that may work, yes. Thank you, let me test that. >>>>>>> Even if that doesn't work right away, but it can be made work, I would >>>>>>> very much prefer that to the driver parsing _DEP for every device in >>>>>>> the namespace by itself. >>>>>> This does work; do you prefer it in scan.c, or in utils.c (in which case >>>>>> with acpi_dep_list declared as external var in internal.h)? >>>>> Let's put it in scan.c for now, because there is the lock protecting >>>>> the list in there too. >>>>> >>>>> How do you want to implement this? Something like "walk the list and >>>>> run a callback for the matching entries" or do you have something else >>>>> in mind? >>>> Something like this (though with a mutex_lock()). It could be simplified >>>> by dropping the prev stuff, but we have seen INT3472 devices with >>>> multiple sensors declaring themselves dependent on the same device >>>> >>>> >>>> struct acpi_device * >>>> acpi_dev_get_next_dependent_dev(struct acpi_device *supplier, >>>> struct acpi_device *prev) >>>> { >>>> struct acpi_dep_data *dep; >>>> struct acpi_device *adev; >>>> int ret; >>>> >>>> if (!supplier) >>>> return ERR_PTR(-EINVAL); >>>> >>>> if (prev) { >>>> /* >>>> * We need to find the previous device in the list, so we know >>>> * where to start iterating from. >>>> */ >>>> list_for_each_entry(dep, &acpi_dep_list, node) >>>> if (dep->consumer == prev->handle && >>>> dep->supplier == supplier->handle) >>>> break; >>>> >>>> dep = list_next_entry(dep, node); >>>> } else { >>>> dep = list_first_entry(&acpi_dep_list, struct acpi_dep_data, >>>> node); >>>> } >>>> >>>> >>>> list_for_each_entry_from(dep, &acpi_dep_list, node) { >>>> if (dep->supplier == supplier->handle) { >>>> ret = acpi_bus_get_device(dep->consumer, &adev); >>>> if (ret) >>>> return ERR_PTR(ret); >>>> >>>> return adev; >>>> } >>>> } >>>> >>>> return NULL; >>>> } >>> That would work I think, but would it be practical to modify >>> acpi_walk_dep_device_list() so that it runs a callback for every >>> consumer found instead of or in addition to the "delete from the list >>> and free the entry" operation? >> >> I think that this would work fine, if that's the way you want to go. >> We'd just need to move everything inside the if (dep->supplier == >> handle) block to a new callback, and for my purposes I think also add a >> way to stop parsing the list from the callback (so like have the >> callbacks return int and stop parsing on a non-zero return). Do you want >> to expose that ability to pass a callback outside of ACPI? > Yes. > >> Or just export helpers to call each of the callbacks (one to fetch the next >> dependent device, one to decrement the unmet dependencies counter) > If you can run a callback for every matching entry, you don't really > need to have a callback to return the next matching entry. You can do > stuff for all of them in one go Well it my case it's more to return a pointer to the dep->consumer's acpi_device for a matching entry, so my idea was where there's multiple dependents you could use this as an iterator...but it could just be extended to that if needed later; I don't actually need to do it right now. > note that it probably is not a good > idea to run the callback under the lock, so the for loop currently in > there is not really suitable for that No problem;  I'll tweak that then >> Otherwise, I'd just need to update the 5 users of that function either >> to use the new helper or else to also pass the decrement dependencies >> callback. > Or have a wrapper around it passing the decrement dependencies > callback for the "typical" users. Yeah that's what I mean by helper; I'll do that then; thanks