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=-3.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED 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 D8E9DC433DB for ; Thu, 21 Jan 2021 06:24:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 804AB2064B for ; Thu, 21 Jan 2021 06:24:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726824AbhAUGY3 (ORCPT ); Thu, 21 Jan 2021 01:24:29 -0500 Received: from youngberry.canonical.com ([91.189.89.112]:43312 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726736AbhAUGXt (ORCPT ); Thu, 21 Jan 2021 01:23:49 -0500 Received: from mail-lj1-f197.google.com ([209.85.208.197]) by youngberry.canonical.com with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.86_2) (envelope-from ) id 1l2TMt-0005zo-M7 for linux-kernel@vger.kernel.org; Thu, 21 Jan 2021 06:22:55 +0000 Received: by mail-lj1-f197.google.com with SMTP id f20so357829ljj.15 for ; Wed, 20 Jan 2021 22:22:55 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=286+aLvFTV4FtvBetACGVIfc0aQZT7xsQ6Fn1YFzNWE=; b=BtQrvkaJQK44Wkez5c4niGT6EkhKiLWJFv4r4Qh77ToNi5Drrk5Kci3GPtDHxY1aqN 6VVxqwsYzjrV33kGVJW5NpkV63gW/8rMDAnD+pGmLB9YVFDTD/RQ4IgOMkbBVTcFtYza K1YgFaG5VHVN79rFk6ATAGwM4O/qT00O0iY+RZor7o5DhwSD3WsYNBEcdC3yCHlaWJxE XNnnAK4H/sONEwS8LLr7h9Nt6nOl2ooGZbXdRDq04f3Ba7DLoty/N0mJvxjC/cJEyXjy G+mPsq425rXrB8TT9i3k4yAFw79CYGQKegkLz2UvA6KS86AUakq3DOj30p3Iw1EqnrMx 1DWg== X-Gm-Message-State: AOAM533YxCHOpLuJiIZbP8wSGCD+Pe+8pkHinkPAiJUy7Iif27Ej93OM Q25qPZfdFpzdmLOk12DAEUUw0n1F0UTRyPIaYT181jXYmsSCusclpoMosr49neOBn0BnrX0ctrE M/OvjscTliX13Xj6gvu6XP6Q0/RpJfw5B/BMAgqToEmfKrKaaeP0SCGNseg== X-Received: by 2002:a2e:8947:: with SMTP id b7mr6258776ljk.116.1611210175143; Wed, 20 Jan 2021 22:22:55 -0800 (PST) X-Google-Smtp-Source: ABdhPJzCYbbieVYKMHA4ivsq3wSRzf1SDvF4od/jM20SWLxethLb+Wu7rnFyvpDvgKmiBX6k5moAFl+6vWRHEoXwphQ= X-Received: by 2002:a2e:8947:: with SMTP id b7mr6258769ljk.116.1611210174921; Wed, 20 Jan 2021 22:22:54 -0800 (PST) MIME-Version: 1.0 References: <20210119081513.300938-1-kai.heng.feng@canonical.com> <20210119094159.GQ4077@smile.fi.intel.com> In-Reply-To: From: Kai-Heng Feng Date: Thu, 21 Jan 2021 14:22:43 +0800 Message-ID: Subject: Re: [PATCH] ACPI / device_sysfs: Use OF_MODALIAS for "compatible" modalias To: Greg Kroah-Hartman Cc: Andy Shevchenko , "Rafael J. Wysocki" , AceLan Kao , "Rafael J. Wysocki" , Mika Westerberg , Len Brown , "open list:ACPI" , open list Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jan 19, 2021 at 6:34 PM Greg Kroah-Hartman wrote: > > On Tue, Jan 19, 2021 at 11:41:59AM +0200, Andy Shevchenko wrote: > > On Tue, Jan 19, 2021 at 04:41:48PM +0800, Kai-Heng Feng wrote: > > > On Tue, Jan 19, 2021 at 4:27 PM Greg Kroah-Hartman > > > wrote: > > > > On Tue, Jan 19, 2021 at 04:15:13PM +0800, Kai-Heng Feng wrote: > > > > ... > > > > > > Who will use OF_MODALIAS and where have you documented it? > > > > > > After this lands in mainline, I'll modify the pull request for systemd > > > to add a new rule for OF_MODALIAS. > > > I'll modify the comment on the function to document the change. > > > > I'm wondering why to have two fixes in two places instead of fixing udev to > > understand multiple MODALIAS= events? > > It's not a matter of multiple events, it's a single event with a > key/value pair with duplicate keys and different values. > > What is this event with different values supposed to be doing in > userspace? Do you want multiple invocations of `modprobe` or something > else? > > Usually a "device" only has a single "signature" that modprobe uses to > look up the correct module for. Modules can support any number of > device signatures, but traditionally it is odd to think that a device > itself can be supported by multiple modules, which is what you are > saying is happening here. > > So what should userspace do with this, and why does a device need to > have multiple module alias signatures? >From the original use case [1], I think the "compatible" modalias should be enough. Andy and Mika, what do you think? Can we remove the ACPI modalias for this case? [1] https://lwn.net/Articles/612062/ Kai-Heng > > thanks, > > greg k-h