From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dan Williams Subject: Re: [PATCH v3 1/2] acpi/nfit: Update nfit driver to comply with ACPI 6.1 Date: Tue, 19 Jun 2018 16:46:27 -0700 Message-ID: References: <1461620099-11933-1-git-send-email-toshi.kani@hpe.com> <1461620099-11933-2-git-send-email-toshi.kani@hpe.com> <1529350667.14039.119.camel@hpe.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: linux-nvdimm-bounces-hn68Rpc1hR1g9hUCZPvPmw@public.gmane.org Sender: "Linux-nvdimm" To: "Elliott, Robert (Persistent Memory)" Cc: "linux-nvdimm-hn68Rpc1hR1g9hUCZPvPmw@public.gmane.org" , "rjw-LthD3rsA81gm4RdzfppkhA@public.gmane.org" , "Moore, Robert" , "linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "linux-acpi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" List-Id: linux-acpi@vger.kernel.org On Tue, Jun 19, 2018 at 12:53 PM, Elliott, Robert (Persistent Memory) wrote: > > >> -----Original Message----- >> From: linux-kernel-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org [mailto:linux-kernel- >> owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org] On Behalf Of Dan Williams >> Sent: Tuesday, June 19, 2018 10:29 AM >> Subject: Re: [PATCH v3 1/2] acpi/nfit: Update nfit driver to comply with >> ACPI 6.1 > ... >> > >> > Here are some examples (kernel 4.17): > > Note that these values were as reported on a little-endian system. > >> Ok, so the lowest significant byte of the Micron id is supposed to be >> 0x2c and this text representation matches that. So the bytes are being >> endian swapped when written to the SPD? > > SPD byte 320 is 0x80. That's the bank number byte (with odd parity). > SPD byte 321 is 0x2c. That's the manufacturer code byte (with odd parity). > > If treated as a single 2-byte value, that is: > * 0x802c (32812 in decimal) if interpreted as big-endian > * 0x2c80 (11392 in decimal) if interpreted as little-endian Ok, JEDEC defines byte 320 as the LSB, so the fact that Linux is showing 0x2c as the LSB is wrong. Linux needs to be fixed.