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 E2FC914386D; Mon, 6 Oct 2025 14:41:45 +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=1759761707; cv=none; b=vERv4E6vVsjfthobS3/llBk9RPT5zJ+S/Xf4Ye5ri0Za6TLq43qmryzLh4qbnj0eU+fC2b6uLw+RuqwKdtYXqNC/FD5XJUA8Yx5wSuOH7UbKPsy2qJlP3C6awSXObJIftVWTSGmivb5Wou/OzyGxDapcucNAmFf0NNfArqKmSSA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1759761707; c=relaxed/simple; bh=4vfoSLZu0iB+MKr7ng9UfsrwpdlYt9d/We31+FzYPxY=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=P1552tRJU8P0gYS0jpSIVAANwRATz088yBE/u6VvzWf3A8FwTgC8NldUvL6V8GTKAyrxjvtdAMnSJuGPUyfiVAVsgHD3UOXUE0pg+aMvZzLkwzHpBrtr9WWjzfuq1VKQRPoYHOO1LqZfeSqYQruzvg/Vkx9H/9G5h62TPqA9fT0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=arm.com; spf=none smtp.mailfrom=foss.arm.com; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=foss.arm.com 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> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: 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