Messages in this thread | | | Date | Thu, 5 Mar 2015 12:56:01 -0800 | Subject | Re: [PATCH 3/3] e820: Add the unknown-12 Memory type (DDR3-NvDIMM) | From | Dan Williams <> |
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On Thu, Mar 5, 2015 at 2:24 AM, Boaz Harrosh <boaz@plexistor.com> wrote: > > There are multiple vendors of DDR3 NvDIMMs out in the market today. > At various stages of development/production. It is estimated that > there are already more the 100ds of thousands chips sold to > testers and sites. > > All the BIOS vendors I know of, tagged these chips at e820 table > as type-12 memory. > > Now the ACPI comity, as far as I know, did not yet define a > standard type for NvDIMM. Also, as far as I know any NvDIMM > standard will only be defined for DDR4. So DDR3 NvDIMM is > probably stuck with this none STD type.
There's no relation between E820 types and DDR technology revisions.
> I Wish and call the ACPI comity to Define that NvDIMM is type-12. > Also for DDR4 > > The motivation of this patch is to be able to differentiate > this NvDIMM type from a real future "unknown-reserved" type. > > In this patch I name type-12 "unknown-12". This is because of > ACPI politics that refuse to reserve type-12 as DDR3-NvDIMM
It's not "politics". Setting standards takes time and the platforms in question simply jumped the gun to enable a proof-of-concept.
> and members keep saying: > "What if ACPI assigns type-12 for something else in future" > > [And I say: Then just don't. Please?]
Once a standard number is assigned, platform firmwares can update type-12 to that number. We might consider a compile time override for these niche/pre-standard systems that can't/won't update, but it's not clear to me that we even need to go that far.
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