From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id BA772448B90; Thu, 24 Sep 2026 10:35:54 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790246156; cv=none; b=PNdwNRME5oOnT3HgARo2GOuNCxzwvdL7hgHfYaqYOmEOkJGpoERgQlsiz+Ab2osRXEvtyPLv8ea+Nut++GzGSogx2JINMz7k/ueSeYBidXxYmv8v+a86VB5DjGcsqSdpat+4Ad3LQfW/Eig1LhDfJnu6jkpbPHfkoiJSuiZDwF8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790246156; c=relaxed/simple; bh=6cyMeBMhrGavK9oDVUWeQnMviClTnzNiDHf2LfBUEFI=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=sM6VgWj3qydBt5DG0iMxhU3MOb1Adyl7AyPZ/w8K6vIeQmEaII98rzvAwfuIPvGEkKSsEW6xLU+Is8GgJyVKax0O1znlPuD0N2scZtEMxZcUemiQIJ2QHGlI/BsvocAY/ybMt8qi/7yTlYQbmqBRA0Mu+sFk2sT5+pF1R1GNKOw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b=UiDcv+bD; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b="UiDcv+bD" Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 558AE1516; Thu, 24 Sep 2026 03:35:50 -0700 (PDT) Received: from [192.168.178.24] (usa-sjc-mx-foss1.foss.arm.com [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id D66343F86C; Thu, 24 Sep 2026 03:35:49 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1790246153; bh=6cyMeBMhrGavK9oDVUWeQnMviClTnzNiDHf2LfBUEFI=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=UiDcv+bDUZWdPZJfaaloYomd7k8j0fBSIHRpGls/xrzxvnzSVPLqHUDPAJ9zwmIT+ WpftGglC7ZUCwPI8q24A+v/3sZK02m1/LND/uqGLBHik19UH1BvfmfUrH1nqaTB2Rq 8cuOdlAWaZB1ohf5s9IiTnqKcp4ZDJtnAsaA9JCo= Message-ID: Date: Thu, 24 Sep 2026 12:35:48 +0200 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v10 12/14] arm_mpam: detect and enable MPAM-Fb PCC support To: Sudeep Holla , Ben Horgan Cc: Lorenzo Pieralisi , Hanjun Guo , Catalin Marinas , Will Deacon , "Rafael J . Wysocki" , Len Brown , James Morse , Reinette Chatre , Fenghua Yu , Jonathan Cameron , Srivathsa L Rao , Ganapatrao Kulkarni , Trilok Soni , Srinivas Ramana , Niyas Sait , Lee Trager , Ritwick Sharma , Gavin Shan , linux-acpi@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org References: <20260911112835.714162-1-andre.przywara@arm.com> <20260911112835.714162-13-andre.przywara@arm.com> <3e7bdafd-d6ea-422c-82ff-e278a17280ff@arm.com> <20260924-snobbish-brainy-velociraptor-06bdd4@sudeepholla> Content-Language: en-GB From: Andre Przywara In-Reply-To: <20260924-snobbish-brainy-velociraptor-06bdd4@sudeepholla> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Hi Sudeep, On 9/24/26 11:48, Sudeep Holla wrote: > On Mon, Sep 21, 2026 at 05:28:27PM +0100, Ben Horgan wrote: >> Hi Andre, >> >> On 21/09/2026 17:09, Andre Przywara wrote: >>> Hi Ben, >>> >>> On 9/11/26 17:09, Ben Horgan wrote: >>>> Hi Andre, >>>> > > [...] > >>>> >>>> This looks like the change earlier in the series to >>>> drivers/acpi/arm64/mpam.c makes no functional effect unless the proposed >>>> spec changes are accepted; the default is msc->id. I'd just move the >>> >>> Yes, but it reduces churn, and more importantly, is more true to the >>> MPAM-Fb spec, which says:"The MSC identifiers are sequential and start from >>> 0 for each agent which uses this protocol." So this requires that we have >>> per-channel IDs for the MSCs, that's why I think it's justified to >>> introduce this already now, even when it's somewhat redundant as the code >>> stands now, as we always assign the system-wide ID to it. >>> >>> I can of course move that out (and have that already on top of v9, >>> internally), but wanted to check this with you. >> >> I don't really mind. If Lorenzo/Sudeep are happy with doing the preparation >> work in drivers/acpi/arm64/mpam.c then I'm ok with it. It's currently a >> non-functional change but does make the expected path forward slightly >> clearer. >> > > Sure, I am okay to have it added here if we plan to use it in the future. > We can always rip it off if the spec changes its direction or gets deemed > as broken 😉. Many thanks, will keep it in then. Cheers, Andre