> -----Original Message----- > From: Dan Williams [mailto:[email protected]] > Sent: Monday, November 6, 2017 5:32 PM > To: Pan, Lijun <[email protected]> > Cc: [email protected] > Subject: Re: [PATCH] acpi/nfit: export read_only attribute of dimms > > On Mon, Oct 30, 2017 at 1:41 PM, Lijun Pan <[email protected]> wrote: > > Though flags attribute provides enough information about > > the dimm, it is nice to export the read_only attribute if > > bit3 of NVDIMM state flag is set. > > If error is injected by BIOS, bit3 and bit1 are both set. > > If DIMM is set to read-only by BIOS, bit3 is set. > > Hence bit3 is good enough to tell whether the dimm is in > > read-only mode or not. > > Hmm, can you say about more about why we need this additional attribute? > > Applications don't read and write the DIMM directly, they only > interface with the DIMM through namespaces of a given region. The > region device already has a 'read_only' attribute. See > read_only_show() in drivers/nvdimm/region_devs.c.
redhat's cockpit can show the server's info like dimm, cpu, network,etc. If the read_only attribute is exported, it is easy for the program to check. I agree read_only status of the specific dimm can be retrieved via checking bit3 of nvdimm state flag, but it is not explicit. If 2 nvdimms are interleaved together, region's read_only only shows that the region is read only, it does not show the 2 underlying physical dimms comprising the region are read only. _______________________________________________ Linux-nvdimm mailing list [email protected] https://lists.01.org/mailman/listinfo/linux-nvdimm
