On Thu, Mar 5, 2015 at 12:56 PM, Dan Williams <[email protected]> wrote: > On Thu, Mar 5, 2015 at 2:24 AM, Boaz Harrosh <[email protected]> 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.
I will be shocked if a standard of this form ever appears. Modern systems *don't have e820*. The BIOSes that are using this type 12 hack are awful throwbacks. --Andy -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
