From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from pandora.armlinux.org.uk (pandora.armlinux.org.uk [78.32.30.218]) (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 4D84A3A8E1; Tue, 9 Jan 2024 15:49:26 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=armlinux.org.uk Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=armlinux.org.uk Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=armlinux.org.uk header.i=@armlinux.org.uk header.b="nN/okoV4" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=armlinux.org.uk; s=pandora-2019; h=Sender: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-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=tZu+pKrUWqvj1u7XXOZ361qKXLT14yOTmWAUg/xb9K8=; b=nN/okoV4vFIiLWpy1C8jbd7tdw Qv36Z2Gb+2ode/mlOC9FGuq844QXK7cH1QtvswvkKjPFNn3crE3ejxFH+peDwTmHOW4G/GWbH6Jpn 0qzKOvO75N3PC9BVsubbFulOPfcPT9peor+qGDaJvLE1hDNNoKtb0pRiolyX60ZvDTRC5WW3imUyZ 1xyVORTa/XshnAfR1BtvDgMDdHcKzUMxaBI9H8XnwA0OUVxFBs03HPJwS8ZWzD+a9pTAz9kjYXkvu D81k2SVTALrUMdf78FrSRpsd/686oC+ZFg2iPb8F+4cDR8NoTEmsESKvjPSBSJuSGwKrJgRpTa/j3 34Jq5IPg==; Received: from shell.armlinux.org.uk ([fd8f:7570:feb6:1:5054:ff:fe00:4ec]:53760) by pandora.armlinux.org.uk with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.96) (envelope-from ) id 1rNELt-0004Hq-18; Tue, 09 Jan 2024 15:49:17 +0000 Received: from linux by shell.armlinux.org.uk with local (Exim 4.94.2) (envelope-from ) id 1rNELr-0004Of-RO; Tue, 09 Jan 2024 15:49:15 +0000 Date: Tue, 9 Jan 2024 15:49:15 +0000 From: "Russell King (Oracle)" To: "Rafael J. Wysocki" Cc: linux-pm@vger.kernel.org, loongarch@lists.linux.dev, linux-acpi@vger.kernel.org, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-riscv@lists.infradead.org, kvmarm@lists.linux.dev, x86@kernel.org, acpica-devel@lists.linuxfoundation.org, linux-csky@vger.kernel.org, linux-doc@vger.kernel.org, linux-ia64@vger.kernel.org, linux-parisc@vger.kernel.org, Salil Mehta , Jean-Philippe Brucker , jianyong.wu@arm.com, justin.he@arm.com, James Morse Subject: Re: [PATCH RFC v3 02/21] ACPI: processor: Add support for processors described as container packages Message-ID: References: Precedence: bulk X-Mailing-List: linux-arch@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: Sender: Russell King (Oracle) On Mon, Dec 18, 2023 at 09:17:34PM +0100, Rafael J. Wysocki wrote: > On Wed, Dec 13, 2023 at 1:49 PM Russell King wrote: > > > > From: James Morse > > > > ACPI has two ways of describing processors in the DSDT. From ACPI v6.5, > > 5.2.12: > > > > "Starting with ACPI Specification 6.3, the use of the Processor() object > > was deprecated. Only legacy systems should continue with this usage. On > > the Itanium architecture only, a _UID is provided for the Processor() > > that is a string object. This usage of _UID is also deprecated since it > > can preclude an OSPM from being able to match a processor to a > > non-enumerable device, such as those defined in the MADT. From ACPI > > Specification 6.3 onward, all processor objects for all architectures > > except Itanium must now use Device() objects with an _HID of ACPI0007, > > and use only integer _UID values." > > > > Also see https://uefi.org/specs/ACPI/6.5/08_Processor_Configuration_and_Control.html#declaring-processors > > > > Duplicate descriptions are not allowed, the ACPI processor driver already > > parses the UID from both devices and containers. acpi_processor_get_info() > > returns an error if the UID exists twice in the DSDT. > > I'm not really sure how the above is related to the actual patch. > > > The missing probe for CPUs described as packages > > It is unclear what exactly is meant by "CPUs described as packages". > > From the patch, it looks like those would be Processor() objects > defined under a processor container device. > > > creates a problem for > > moving the cpu_register() calls into the acpi_processor driver, as CPUs > > described like this don't get registered, leading to errors from other > > subsystems when they try to add new sysfs entries to the CPU node. > > (e.g. topology_sysfs_init()'s use of topology_add_dev() via cpuhp) > > > > To fix this, parse the processor container and call acpi_processor_add() > > for each processor that is discovered like this. > > Discovered like what? > > > The processor container > > handler is added with acpi_scan_add_handler(), so no detach call will > > arrive. > > The above requires clarification too. The above comments... yea. As I didn't write the commit description, but James did, and James has basically vanished, I don't think these can be answered, short of rewriting the entire commit message, with me spending a lot of time with the ACPI specification trying to get the terminology right - because at lot of the above on the face of it seems to be things to do with wrong terminology being used. I wasn't expecting this level of issues with this patch set, and I now feel completely out of my depth with this series. I'm wondering whether I should even continue with it, since I don't have the ACPI knowledge to address a lot of these comments. -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTP is here! 80Mbps down 10Mbps up. Decent connectivity at last!