Re: [RFC PATCH] Fix _FIT vs. NFIT processing breakage

["Verma, Vishal L" <vishal.l.verma@intel.com>]

On Wed, 2015-11-18 at 15:22 -0700, Toshi Kani wrote:
> On Wed, 2015-11-18 at 16:28 -0500, Linda Knippers wrote:
> > On 11/18/2015 4:07 PM, Verma, Vishal L wrote:
> > > On Wed, 2015-11-18 at 12:54 -0500, Linda Knippers wrote:
> > > > Since commit 209851649dc4f7900a6bfe1de5e2640ab2c7d931, we no
> > > > longer
> > > > see NVDIMM devices on our systems.  The NFIT/_FIT processing at
> > > > initialization gets a table from _FIT but doesn't like it.
> > > > 
> > > > When support for _FIT was added, the code presumed that the data
> > > > returned by the _FIT method is identical to the NFIT table,
> > > > which
> > > > starts with an acpi_table_header.  However, the _FIT is defined
> > > > to return a data in the format of a series of NFIT type
> > > > structure
> > > > entries and as a method, has an acpi_object header rather tahn
> > > > an acpi_table_header.
> > > 
> > > Hm, I couldn't find any reference to this in the spec - that NFIT
> > > will
> > > have the acpi_table_header but _FIT will have a different header -
> > > but
> > > I'm no ACPI expert - is this usual convention? Any pointers where
> > > I
> > > could look at?
> > 
> > I'm no ACPI expert either so maybe Toshi or someone else will help
> > me
> > here but according to the FW developer, the convention is that there
> > is
> > no ACPI table header because you already know what the table is.
> 
> map_mat_entry() handles _MAT for processor objects, which expects no
> MADT header
> table.

Ok, thanks for the clarifications. I'm fine with the fix. Could you
resend an updated patch without the extra debug. We'd also have to
update the unit test framework - in tools/testing/nvdimm/test/nfit.c, in
nfit_test0_setup, based on whether it is being called with the hotplug
flag or not, decide which header to include.

Thanks,
	-Vishal

> 
> Thanks,
> -Toshi 
> 
> > Also, if you look at the NFIT definition (table 5-126) , the
> > definition
> > explicitly includes the APCI table header but the _FIT definition
> > does not.
> > It just says it's a series of NFIT Types structure entries.
> > 
>