From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=217.140.110.172 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794514666; b=fA9K7kVt/qnNxbukVWbjc+mTbjEsT0nMoRXXcoqIT4KEmPs+WuiI12umMOQIs5q3LLlk XkT4HT05BmicQaPTSS2TKYAW2yGqAeIG8bilL6ni/2ZjfrhKAtP3gMbA3NktaeqxGrYKF zmXFBKARel3z+Ee0RTj+rxZ2j8RIfxWLZr9dkuI/mQdvjBKWbJC1Ys4Ohl2tD521l06/6 iZ1nCDqGQxwbTvxJ4UsBrvDrai0kR6fHwhHlpGHvpB/vLbqPEPs3ERTHOxo/z/yQ4m3iz wYXwRz3EmltNuyTYzmbPRsQsgTM+6TC+AdwHQx3+fKNhzECv8dLXXuFoHxfGcZ2NNbQ== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794514666; h=DMARC-Filter:Received:Received:DKIM-Signature:Date:From:To:Cc: Subject:Message-ID:References:MIME-Version:Content-Type: Content-Disposition:In-Reply-To; bh=vlZqzvtO/HmxUCVMk4ClrKPfCBbBD3nwIw0Aqx6q7s8=; b=sFFSoefCZREAgkRlkhMJaFBUoMr1vesScLpnVUIt4+WR5eDlwlm/Q+XGWJCfBs4GM6Ri xgeBnlow1qAiOz5Modeby9epWvkbC3hiub+MVJ8vhyhxqyrqMal/aU+ispo8cSSuxumEn vchuzWqs/3nJl94XqObFLmJzeD8S+6yW4w00S3ilqp27X6hcvJ4JH/OmtFIeAo5fRde+P P4Ox0dMYSuR3vqEOv2o81PQb0F2KwCT+3YfJ+7VG+2IslipNaVLGjT/lFlxBcQNs4xjp7 91HCGX8mT3O1y7RQ9HJpivV10dLei3NACzo5i4uIktXspBVp92cYF17ee0U0qiHf7rw== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass header.from=arm.com; spf=pass smtp.mailfrom=arm.com; dkim=pass header.d=arm.com header.i=@arm.com header.a=rsa-sha256 header.s=foss header.b=Jq7zX7UP; arc=none smtp.remote-ip=217.140.110.172 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 89FF3606A31C; Thu, 12 Nov 2026 20:17:45 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org 89FF3606A31C 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, unprotected) header.d=arm.com header.i=@arm.com header.a=rsa-sha256 header.s=foss header.b=Jq7zX7UP 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 999E91476; Thu, 12 Nov 2026 12:17:41 -0800 (PST) Received: from pluto (usa-sjc-mx-foss1.foss.arm.com [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id C24143F85F; Thu, 12 Nov 2026 12:17:41 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1794514664; bh=DnwmvWTMD0sYcZHcAwFeqJGrssc3hWAPd1jsUWH9nHg=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Jq7zX7UPusnlrQDCRHmcPNVl/vzqAPi+FegZnwm3Pt1YkHaYivIZr71Q5Drr84h3q jz0ToTS4kG49dKWJZ/N5/ZJWJSNWuMDd578NPEuGqhVAmmghvcy+m/z7Wlgc9nlwG8 aMukWx6kAdWikQyxq87aS9kWk0f0h7pze288UyMw= Date: Thu, 12 Nov 2026 20:17:35 +0000 From: Cristian Marussi To: Jonathan Cameron Cc: Cristian Marussi , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, arm-scmi@vger.kernel.org, linux-doc@vger.kernel.org, sudeep.holla@kernel.org, james.quinlan@broadcom.com, f.fainelli@gmail.com, vincent.guittot@linaro.org, etienne.carriere@st.com, peng.fan@oss.nxp.com, michal.simek@amd.com, d-gole@ti.com, elif.topuz@arm.com, lukasz.luba@arm.com, philip.radford@arm.com, david@kernel.org, souvik.chakravarty@arm.com, leitao@kernel.org, kas@kernel.org, puranjay@kernel.org, usama.arif@linux.dev, kernel-team@meta.com Subject: Re: [PATCH v15 23/35] firmware: arm_scmi: Add Telemetry generation counter event Message-ID: References: <20261109091221.2532706-1-cristian.marussi@arm.com> <20261109091221.2532706-24-cristian.marussi@arm.com> <20261110144635.00005964@oss.qualcomm.com> X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20261110144635.00005964@oss.qualcomm.com> On Tue, Nov 10, 2026 at 02:46:35PM -0800, Jonathan Cameron wrote: > On Mon, 9 Nov 2026 09:12:09 +0000 > Cristian Marussi wrote: > > > Add a per-instance generation counter to track configuration changes which > > uses the common telemetry events framework. > Why? What's the usecase for this? > Needs some more information or I'd leave it for now. > SCMI Telemetry is specified and designed FW/Kernel side to allow for multiple readers and multiple writers issuing configuration changes: give that there is NO HW/FW/SPEC limitation in allowing such concurrency (unlike e.g. for a serial or an RTC) the telemetry driver does NOT enfroce any kind of exclusive access...last one wins when multiple acctors tries to configure overlapping stuff...none of kernel problem userspace should co-ordinate...and I suspect most of the time having multiple apps trying to concurrently issue conflicting Telemetry request would be a matter of wrong platform configuration/setup (similarly to what would happen by running together all the lovely varied network configiratio solution on a Linux box...) As said the Kernel SHOULD NOT care, going back to the networking example Kernel indeed does NOT active policy netlink access..you are free to shot into your foot... Anyway, co-ordinating access to the Telemetry resources in userspace can be a pain, so the the generation counter is an optional mechanism to be alerted when some of the Telemetry has been changed, so that userspace can spot that something odd is happening (if it was unexpected) and avoid to sample and analyze bogus data... The generic event support upon which this is based, it is meant to support future events like relaying notifications to userspace...but given that notifs were NOT implemented for real, it is not present (NOR the related ABI...) Thanks, Cristian