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Mon, 01 Feb 2021 13:55:23 -0800 (PST) MIME-Version: 1.0 References: <20210130002438.1872527-1-ben.widawsky@intel.com> <20210130002438.1872527-6-ben.widawsky@intel.com> <20210201171051.m3cbr3udczxwghqh@intel.com> <4d62a125-91e1-d32-66d3-1216d751f9b8@google.com> In-Reply-To: <4d62a125-91e1-d32-66d3-1216d751f9b8@google.com> From: Dan Williams Date: Mon, 1 Feb 2021 13:55:20 -0800 Message-ID: Subject: Re: [PATCH 05/14] cxl/mem: Register CXL memX devices To: David Rientjes Cc: Ben Widawsky , linux-cxl@vger.kernel.org, Linux ACPI , Linux Kernel Mailing List , linux-nvdimm , Linux PCI , 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" Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Feb 1, 2021 at 1:53 PM David Rientjes wrote: > > On Mon, 1 Feb 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. > > > > Makes sense, can we add that these are expressed in bytes or is that > already implied? Makes sense to declare units here.