From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 633E03F8231; Thu, 15 Oct 2026 18:42:46 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792089768; cv=none; b=fZxrNb390QfsHbH9P4MQe+FdsXw3z+aOgwobhaump5002brK7G5vfUNJnwC9YROwsg0cJ8OYstb7s6Y3qvwA4jn7xwbPqKPkkqVoAjmM17sbKwYkRtCcCFo8Z6frDj1Ln3fOEbZGQT1V5xXpbfoi9121fLO3Y5oVwdEdtgvryXg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792089768; c=relaxed/simple; bh=tDYWq06Lr0v8aO4d/FRTH+CAmRSgkd1Ug4MoqdpKYsg=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=FWcdTPylywntQXNJ+tiwqApJbSIz+sOCRv9MPZ39pIK/puVEweepqZX+YNXs/5qa4pfuU8JZXUvlP6wNSLyzAaT6U888mxGo0emxlpvqdrh9RuPrMD7kPKYQcQ2/M6Vhw70CTwhdCS1pIVx3aLQ30qu5yIMUh09TRA7/L80PRpE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=D5ALtjyC; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="D5ALtjyC" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1FF051F000C4; Thu, 15 Oct 2026 18:42:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1792089765; bh=dg/1OSkrW8sX2euc3aZ8a5bssRkph0JoeOFI3JZD560=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=D5ALtjyC68GN/mpi+ZK8E1mWTMEDomCnS/ERWCEN6bBJPQCtugUMl+B22l+1wJ87o Hf+WjNfvU8VHb/MOo35aSpSbbtiJhvFwkuvJy8SdvTs4tED3cQebluDVjjUjxXz1RV 10NtAzv7C/NQEJIftkQyH6he5O0wyi7/R2K/bcps+aobJQauR6XU/5Rlvb/ksM6j/L 59oVD/dzJZQhZZ9ETV4mkQ0Wny9IbBXisFIw8Uq9voEdcR0398E47anliP1+RMUf+R NcmjNIg3KkyRf2CsCMhsGMRZueAB/J4ydYChvpem9THId0Ab9GKuFOOBhOgZqJyrv/ Y3fVl4kmGEfLQ== Message-ID: Date: Thu, 15 Oct 2026 13:42:43 -0500 Precedence: bulk X-Mailing-List: linux-acpi@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v1 3/4] platform profile: Add firmware-neutral aggregate sysfs interface Content-Language: en-US To: "Rafael J. Wysocki (Intel)" Cc: Mark Pearson , Armin Wolf , Daniel Lezcano , Hans de Goede , Jonathan Corbet , Shuah Khan , Viresh Kumar , =?UTF-8?Q?Ilpo_J=C3=A4rvinen?= , Maximilian Luz , Shyam Sundar S K , "Derek J . Clark" , Daniel Lezcano , Zhang Rui , Lukasz Luba , Jai Luthra , Greg KH , Jack Wu , "linux-acpi@vger.kernel.org" , linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-pm@vger.kernel.org, "platform-driver-x86@vger.kernel.org" , Kurt Borja References: <20261014132500.3817549-1-daniel.lezcano@oss.qualcomm.com> <20261014132500.3817549-4-daniel.lezcano@oss.qualcomm.com> <1cba0f2a-38cd-42b2-a773-9dca5d7519e5@app.fastmail.com> <68128016-661b-4b78-bac1-b7e23029d8de@kernel.org> From: Mario Limonciello In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit On 10/15/26 13:33, Rafael J. Wysocki (Intel) wrote: > On Thu, Oct 15, 2026 at 8:28 PM Mario Limonciello wrote: >> >> On 10/15/26 13:04, Mark Pearson wrote: >>> >>> On Thu, Oct 15, 2026, at 7:30 AM, Rafael J. Wysocki (Intel) wrote: >>>> On Wed, Oct 14, 2026 at 11:31 PM Armin Wolf wrote: >>>>> >>>>> Am 14.10.26 um 15:24 schrieb Daniel Lezcano: >>>>> >>>>>> The per-provider class interface is firmware-independent, but system- >>>>>> wide profile selection is only exposed under /sys/firmware/acpi. >>>>>> >>>>>> Add /sys/kernel/platform_profile/{choices,profile}, sharing the existing >>>>>> aggregate callbacks and semantics with the legacy interface. Keep >>>>>> attributes hidden until a provider is registered and remove them after >>>>>> the last provider. >>>>>> >>>>>> Notify both aggregate frontends on profile changes. Also notify the >>>>>> provider class device on a direct profile write, matching its documented >>>>>> POLLPRI ABI. Restore aggregate visibility after a failed registration. >>>>> >>>>> IMHO the aggregate sysfs interface only exists for backwards-compatibility, >>>>> so i would be very happy if you could just make the associated code optional >>>>> and instead teach platform-profiles-daemon to use the individual class devices >>>>> instead. >>>> >>>> It is not just a matter of opinion AFAICS, the aggregate interface has >>>> been regarded as legacy for quite a while (see commit 778b94d7ac17 >>>> "ACPI: platform_profile: Add support for hidden choices" for example) >>>> and it was retained exactly for backwards compatibility reasons IIRC. >>>> >>>> I'm with Armin on this. >>>> >>>> Thanks! >>> >>> I don't think we can get rid of the legacy aggregate interface - which I think is what you and Armin are asking for? What does making it optional mean? >>> >>> Reading through the patch series it seemed quite reasonable to me to move it out from under ACPI but still have the old interface working. What are the alternatives? >>> >>> User space (and users) are still using the aggregate interface in my experience >>> >>> Mark >> >> If we want to get rid of the legacy interface eventually I think this is >> how you can do it: >> >> 1) Wrap it with a boolean Kconfig. Default to enabled. >> 2) Add some messaging in this Kconfig that it's being removed after the >> LTS kernel from 2028. >> 3) Emit a pr_notice_once() or similar that it's deprecated and will be >> removed in the future. >> 4) Modify all (known) userspace software to stop using it. >> 5) Wait for userspace software to tag new releases. >> 6) Change default to disabled. >> 7) Wait some time. >> 7) Next LTS is declared. >> 7) Drop kconfig and legacy code. > > That should work, but my point is rather to avoid adding another > aggregate interface to replace the old one and instead switch over the > ecosystem to the existing (and documented) class device platform > profile interface. > > The legacy aggregate one may simply be removed when everybody stops > using it (which may take a while and it may be moved to staging at one > point). Right totally agreed. I was meaning userspace software should switch to class interfaces not add a new aggregate one.