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 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 45943CCA471 for ; Mon, 6 Oct 2025 14:41:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To: Content-Transfer-Encoding:Content-Type:MIME-Version:References:Message-ID: Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=Cjg8EJYcVTI9rTTTcx4cj4rR0+h1zQf26NxqhwPN2QA=; b=CkYocstTK1q6hyGfjrK2uvLUJV nFpCFCLvj8US+tVhoq66nhV1xXDEqk/b5PfYiWXUbBocaymL8o2PnbssXjnewvPlWZGWa6iDuGWph 8UWWCXmswGI0fQo8iYctE9RDmwyvZWdaboT/854QGiYfPGXXyv4yNR+Xu2zeoh19r+nCP+0JBpKws nrnuQJN06EiDoiUim1TuddDP2Zo+fHmsljk8FiF75EMIJYRsqfnVIJROzum23WFDmIv/gUvxWWv0Y dN/UCKMosXJUc7JevThcsPUuGr1HX44mKiEEpxTNAYxzoiSkoLgtI7GtuZ3EkvrCi4NhFIu3eNjuY OLRkVUFA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1v5mPM-00000000CJF-1i7B; Mon, 06 Oct 2025 14:41:48 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1v5mPK-00000000CIj-1coZ for linux-arm-kernel@lists.infradead.org; Mon, 06 Oct 2025 14:41:47 +0000 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 0DBD91515; Mon, 6 Oct 2025 07:41:37 -0700 (PDT) Received: from bogus (e133711.arm.com [10.1.196.55]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id D62923F738; Mon, 6 Oct 2025 07:41:42 -0700 (PDT) Date: Mon, 6 Oct 2025 15:41:40 +0100 From: Sudeep Holla To: Ulf Hansson Cc: "Rafael J . Wysocki" , Sudeep Holla , Catalin Marinas , Will Deacon , Mark Rutland , Thomas Gleixner , Maulik Shah , Daniel Lezcano , Vincent Guittot , linux-pm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 2/3] arm64: smp: Implement cpus_has_pending_ipi() Message-ID: <20251006-spiked-beige-gecko-6d8748@sudeepholla> References: <20251003150251.520624-1-ulf.hansson@linaro.org> <20251003150251.520624-3-ulf.hansson@linaro.org> <20251006-manipulative-urban-antelope-31101f@sudeepholla> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20251006_074146_462709_7D9FD39D X-CRM114-Status: GOOD ( 16.97 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Mon, Oct 06, 2025 at 02:22:49PM +0200, Ulf Hansson wrote: > On Mon, 6 Oct 2025 at 12:54, Sudeep Holla wrote: > > > > 2. I understand this is intended for the DragonBoard 410c, where the firmware > > can’t be updated. However, ideally, the PSCI firmware should handle checking > > for pending IPIs if that’s important for the platform. The firmware could > > perform this check at the CPU PPU/HW level and prevent entering the > > state if needed. > > I think this is exactly what is happening on Dragonboard 410c (see the > stats I shared in the commit message in patch3). > > The PSCI FW refuses to enter the suggested idlestate and the call fails. > Ah OK, the PSCI FW is doing the job correctly, we are just attempting to reduce the failures by catching few cases earlier in the OSPM itself ? Sure it only reduces the failures but it can't eliminate those as IPI might be issued after this check in the OSPM. I understand the call to firmware can be prevented. -- Regards, Sudeep