On Wed, Apr 22, 2015 at 11:23 AM, Toshi Kani <toshi.k...@hp.com> wrote: > On Wed, 2015-04-22 at 11:20 -0700, Dan Williams wrote: >> On Wed, Apr 22, 2015 at 11:00 AM, Linda Knippers <linda.knipp...@hp.com> >> wrote: >> Wait, point of clarification, DCRs (dimm-control-regions) have RFICs, >> not MEMDEVs (memory-device-to-spa-mapping). Toshi's original report >> was that an NFIT with a SPA+MEMDEV was failing to enable a PMEM >> device. That specific problem can be fixed by either deleting the >> MEMDEV, or adding a DCR. > > By a DCR, do you mean a DCR structure or SPA with Control Region GUID?
Hmm, I meant a DCR as defined below. I agree you would not need a "SPA-DCR". > Adding a DCR structure does not solve this issue since it requires SPA > with Control Region GUID, which battery-backed DIMMs do not have. I would not go that far, half of a DCR entry is relevant for any NVDIMM, and half is only relevant if a DIMM offers BLK access: struct acpi_nfit_dcr { u16 type; u16 length; u16 dcr_index; u16 vendor_id; u16 device_id; u16 revision_id; u16 sub_vendor_id; u16 sub_device_id; u16 sub_revision_id; u8 reserved[6]; u32 serial_number; u16 fic; <<<<< BLK relevant fields start here <<<<< u16 num_bcw; u64 bcw_size; u64 cmd_offset; u64 cmd_size; u64 status_offset; u64 status_size; u16 flags; u8 reserved2[6]; }; >> Of course, if you add a DCR with a different intended DSM layout than >> the DSM-example-interface the driver will need to add support for >> handling that case. > > Yes, we consider to add different _DSMs for management. We do not need > the nd_acpi driver to support it now, but we need this framework to work > without the DSM-example-interface present. > One possible workaround is that I could ignore MEMDEV entries that do not have a corresponding DCR. This would enable nd_namespace_io devices to be surfaced for your use case. Would that work for you? I.e. do you need the nfit_handle exposed? -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/