Re: [PATCH v3 1/2] acpi/nfit: Update nfit driver to comply with ACPI 6.1

From: Kani, Toshi
Date: Mon Jun 18 2018 - 15:39:44 EST


On Mon, 2018-06-18 at 12:01 -0700, Dan Williams wrote:
> On Mon, Apr 25, 2016 at 2:43 PM Toshi Kani <toshi.kani@xxxxxxx> wrote:
> >
> > ACPI 6.1, Table 5-133, updates NVDIMM Control Region Structure
> > as follows.
> > - Valid Fields, Manufacturing Location, and Manufacturing Date
> > are added from reserved range. No change in the structure size.
> > - IDs (SPD values) are stored as arrays of bytes (i.e. big-endian
> > format). The spec clarifies that they need to be represented
> > as arrays of bytes as well.
> >
>
> Circling back on this a couple years too late... where are you reading
> this "arrays of bytes" note. As far as I can see this is wrong. JEDEC
> says that vendor id is stored LSB of the id is stored at the lowest
> byte in SPD, which is little endian. So it seems Linux has showing the
> incorrect value for a long time now.

This follows ACPI 6.2a section 5.2.25.10 NVDIMM Representation Format,
which Robert cited in his comment below:
https://patchwork.kernel.org/patch/10237609/

Thanks,
-Toshi