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 X-Spam-Level: X-Spam-Status: No, score=-8.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 82415C433DB for ; Mon, 1 Feb 2021 17:11:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4A16E61481 for ; Mon, 1 Feb 2021 17:11:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231646AbhBARLn (ORCPT ); Mon, 1 Feb 2021 12:11:43 -0500 Received: from mga04.intel.com ([192.55.52.120]:58996 "EHLO mga04.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229599AbhBARLe (ORCPT ); Mon, 1 Feb 2021 12:11:34 -0500 IronPort-SDR: QgyF0Z6EBtn3RwR8+WhIQw5DjW+pGNhuuz3EbZoP8aQDa+JqIVk0tTnbBtxNOCbRZ/SrMXj+j2 UAuM2KXcPpTQ== X-IronPort-AV: E=McAfee;i="6000,8403,9882"; a="178155859" X-IronPort-AV: E=Sophos;i="5.79,393,1602572400"; d="scan'208";a="178155859" Received: from orsmga001.jf.intel.com ([10.7.209.18]) by fmsmga104.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 01 Feb 2021 09:10:53 -0800 IronPort-SDR: HBYH405ROlMEXT03PmawXS4NPL/f9eJXfesa31754JNg5yULll9HHRdK5HY/0W32JLDR6YU/lE D8fqecKtWQ/Q== X-IronPort-AV: E=Sophos;i="5.79,393,1602572400"; d="scan'208";a="432430624" Received: from jambrizm-mobl1.amr.corp.intel.com (HELO intel.com) ([10.252.133.15]) by orsmga001-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 01 Feb 2021 09:10:52 -0800 Date: Mon, 1 Feb 2021 09:10:51 -0800 From: Ben Widawsky To: David Rientjes Cc: linux-cxl@vger.kernel.org, Dan Williams , linux-acpi@vger.kernel.org, linux-kernel@vger.kernel.org, linux-nvdimm@lists.01.org, linux-pci@vger.kernel.org, Bjorn Helgaas , Chris Browy , Christoph Hellwig , Ira Weiny , Jon Masters , Jonathan Cameron , Rafael Wysocki , Randy Dunlap , Vishal Verma , daniel.lll@alibaba-inc.com, "John Groves (jgroves)" , "Kelley, Sean V" Subject: Re: [PATCH 05/14] cxl/mem: Register CXL memX devices Message-ID: <20210201171051.m3cbr3udczxwghqh@intel.com> References: <20210130002438.1872527-1-ben.widawsky@intel.com> <20210130002438.1872527-6-ben.widawsky@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 21-01-30 15:52:01, David Rientjes wrote: > On Fri, 29 Jan 2021, Ben Widawsky wrote: > > > diff --git a/Documentation/ABI/testing/sysfs-bus-cxl b/Documentation/ABI/testing/sysfs-bus-cxl > > new file mode 100644 > > index 000000000000..fe7b87eba988 > > --- /dev/null > > +++ b/Documentation/ABI/testing/sysfs-bus-cxl > > @@ -0,0 +1,26 @@ > > +What: /sys/bus/cxl/devices/memX/firmware_version > > +Date: December, 2020 > > +KernelVersion: v5.12 > > +Contact: linux-cxl@vger.kernel.org > > +Description: > > + (RO) "FW Revision" string as reported by the Identify > > + Memory Device Output Payload in the CXL-2.0 > > + specification. > > + > > +What: /sys/bus/cxl/devices/memX/ram/size > > +Date: December, 2020 > > +KernelVersion: v5.12 > > +Contact: linux-cxl@vger.kernel.org > > +Description: > > + (RO) "Volatile Only Capacity" as reported by the > > + Identify Memory Device Output Payload in the CXL-2.0 > > + specification. > > + > > +What: /sys/bus/cxl/devices/memX/pmem/size > > +Date: December, 2020 > > +KernelVersion: v5.12 > > +Contact: linux-cxl@vger.kernel.org > > +Description: > > + (RO) "Persistent Only Capacity" as reported by the > > + Identify Memory Device Output Payload in the CXL-2.0 > > + specification. > > Aren't volatile and persistent capacities expressed in multiples of 256MB? As of the spec today, volatile and persistent capacities are required to be in multiples of 256MB, however, future specs may not have such a requirement and I think keeping sysfs ABI easily forward portable makes sense.