Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753947AbbDVT2V (ORCPT ); Wed, 22 Apr 2015 15:28:21 -0400 Received: from mail-wg0-f52.google.com ([74.125.82.52]:34347 "EHLO mail-wg0-f52.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753716AbbDVT2S (ORCPT ); Wed, 22 Apr 2015 15:28:18 -0400 MIME-Version: 1.0 In-Reply-To: <1429727038.16996.16.camel@misato.fc.hp.com> References: <20150418013256.25237.96403.stgit@dwillia2-desk3.amr.corp.intel.com> <20150418013535.25237.4770.stgit@dwillia2-desk3.amr.corp.intel.com> <1429644912.17259.31.camel@misato.fc.hp.com> <1429646156.17259.39.camel@misato.fc.hp.com> <1429720742.15952.30.camel@misato.fc.hp.com> <5537E1D9.6010609@hp.com> <1429727038.16996.16.camel@misato.fc.hp.com> Date: Wed, 22 Apr 2015 12:28:17 -0700 Message-ID: Subject: Re: [Linux-nvdimm] [PATCH 04/21] nd: create an 'nd_bus' from an 'nfit_desc' From: Dan Williams To: Toshi Kani Cc: Linda Knippers , "linux-kernel@vger.kernel.org" , "linux-nvdimm@lists.01.org" Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2340 Lines: 61 On Wed, Apr 22, 2015 at 11:23 AM, Toshi Kani wrote: > On Wed, 2015-04-22 at 11:20 -0700, Dan Williams wrote: >> On Wed, Apr 22, 2015 at 11:00 AM, Linda Knippers 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 majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/