From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 491E9221F20 for ; Thu, 18 Jun 2026 20:21:17 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781814078; cv=none; b=XmKIFn35xx9h3Wal6p509fgwhc5JRHsLsWwXK+oKuNcElqFmtb06bW+i8FxHuRECpaf0VgVQo6rnw7G+NOrbSWt1xNoIv0JjQER7cSD3OqL8Fgk11QtvvQ6anEN0bguI7qfs2Wx/RKk5IhYoZ2waMA1uGyEWBNX306a60hder0Q= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781814078; c=relaxed/simple; bh=iWT+qFZ8akk70Yu23JoTJYfgUgObRmSsSv8aHyo13dI=; h=Date:From:To:Cc:Message-ID:In-Reply-To:References:Subject: Mime-Version:Content-Type; b=t1TBzfWES1jg783d9udcVmBsVIyak0TEMgyem3lF2qXHq3S+FOAcvEpgEjyqktqRZ3gBTHCGzzn2iHoQY0tUts17KCYFL71h6UrA14pv7Y+trSqQ9VqW5GcsmQ3pRjchTSX4mX5EnT/numlxPUH5LFvEUD3usT+FEiCA+gtvVxM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=KdpsdITJ; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="KdpsdITJ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A041B1F00A3A; Thu, 18 Jun 2026 20:21:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1781814077; bh=aZ30rkY6fS83NCgqNmS+ptIKL+DjMGIyFj15frsFJQs=; h=Date:From:To:Cc:In-Reply-To:References:Subject; b=KdpsdITJeQHgSmpqKq2UztrCsVjnm2bhB8/r+Om1j9qhYjHE/UO5XryJKskXNHYWM ETGsZzHLlkcdWH6Wb1DtbOSVR8z4fZBBUntw7sap67GMlxsdsT9z48qCXXfLciRFh4 QyleSgj6YYvQhRZ/TLZijmqAqpQOT2I9DMn6c85GA07sUTaJdoVl3GSbZasfkB+X2+ tBEPGyR5Pc4IAv/dOfX4sz1svueJ1sVxe+3+0kwZbWb3KgwjkOljeVzHdP6jNIwe21 DHO5JZeHkAQ66NoJdLjZMOLFkMt62tghiE5X2bTajtdmFPiMn8jGvZv/jm3X/re3WP pL+qSQPSWpfMA== Received: from phl-compute-12.internal (phl-compute-12.internal [10.202.2.52]) by mailfauth.phl.internal (Postfix) with ESMTP id DA554F4007D; Thu, 18 Jun 2026 16:21:15 -0400 (EDT) Received: from phl-frontend-04 ([10.202.2.163]) by phl-compute-12.internal (MEProxy); Thu, 18 Jun 2026 16:21:15 -0400 X-ME-Sender: X-ME-Received: X-ME-Proxy-Cause: dmFkZTEhHMDBCmbbuuEzAkjQa+xVRVg1pXOIKKbFjE8CkLdbCvLexC835JvhvihDO7WJWU VmSSK/SoQJ2K/G9nB6X94J970u99PrBGykcXhzPIcJzjvNDe2Q6ftR5c24+cudL2QbUAL2 4OV/V+8Qi3Wh8DW0pEYlyefFX//g58V6oCMUiZw6PLZVO/lc8DhOjSpwyVzM9SOMF/2X76 APo9eCFdUs0GTkMa6aKgkhTfit0BUU9M/mGOA1bs2hnvmBJJJ1xPbSDxVUFizXjxFEBpNC C2VxtLSMGErOfZyn9QDHQYX6c19EWe/JOIRzz4fobxLDUwT6KLX0MChqET+FjM6/19yHN1 hvySMHI3giy7aeti1KSN37RZqo3wfdV4R/oXKmBf94WajsfrVVUndiRVa7A3hMqQTIWxVB FeuBfdi83envkQioYY4MJyk0QSkeNHGcrQnPFnQHQoh6j3MgxR64ri9x6p6T5wfMFf8t6B A2ndJJUVOGy7IaK1L6ZYMlkvQxgW/+fS8cYF1pqtZzeItSv0pa0jyntKQgiHhaGdv7l06O QA8fwubtLoi6wlPdz8Giz+yptzNGFd7ff79+4idN+e07VZwmZZ4BECSVJyenWUdrlESC2A WVjXViBDcoS/62ShmD1NBua/E0Ujq7cyOZLYlJrHaNLVjft908P19nWV9JRQ X-ME-Proxy: Feedback-ID: i67ae4b3e:Fastmail Received: by mail.messagingengine.com (Postfix) with ESMTPA; Thu, 18 Jun 2026 16:21:15 -0400 (EDT) Date: Thu, 18 Jun 2026 13:21:14 -0700 From: "Dan Williams (nvidia)" To: Dave Jiang , linux-cxl@vger.kernel.org, linux-pci@vger.kernel.org Cc: terry.bowman@amd.com, bhelgaas@google.com, jic23@kernel.org, djbw@kernel.org Message-ID: <6a34533a43730_299c3a10060@djbw-dev.notmuch> In-Reply-To: <20260618170723.2010490-1-dave.jiang@intel.com> References: <20260618170723.2010490-1-dave.jiang@intel.com> Subject: Re: [RFC PATCH v2 0/2] PCI/CXL: Add RDPAS support for CXL.io Precedence: bulk X-Mailing-List: linux-pci@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Dave Jiang wrote: > v2: > - Added multiple DSP per RCEC support. > - Added boundary checks for reading MMIO > - Addressed issues raised by shashiko > - See individual patches for detailed changes > > The series add RCEC Downstream Port Assocation Structure (RDPAS) parsing > support to CXL.io. RDPAS is an ACPI table that is part of the CXL Early > Discovery Table (CEDT) defined in CXL specification r4.0 9.18.1.5. It > provides the mapping between RCEC and downstream ports. With RDPAS, the > error device can be directly found when an error is reported on RCEC, > without walking a number of RCiEP in order to determine which one reported > the error. While CXL.cachemem is supported by RDPAS, there is no easy way > to discover the source id of the error and therefore finding the Linux PCI > object for the RCiEP. The intention here is to accelerate the discovery > of the error by directly locating the error device with the given > information. Can you clarify why this "acceleration" matters in practice, especially when Linux needs to be prepared for the RDPAS to not be present? Did RDPAS ever ship on a CXL platform? > This series is based on top of Terry's CXL error protocol series [1]. > Looking for comments on the series WRT if it makes sense to add on top > of Terry's error handling for RCH/RCD devices. What is the correlation with Terry's CXL.cachemem protocol series when this implementation claims to only support CXL.io and Terry's series is about CXL.cachemem protocol errors?