[PATCH 0/3] fix NVDIMM hotplug changes

[Linda Knippers <linda.knippers@hpe.com>]

Since commit 209851649dc4f7900a6bfe1de5e2640ab2c7d931 
("acpi: nfit: Add support for hot-add"), we no longer see 
NVDIMM devices on our NVDIMM-N systems.  The NFIT/_FIT processing 
at initialization gets a table from _FIT but thinks it is 
malformed and exits, leaving us with no NFIT at all.

This series fixes the problem caused by a difference in ACPI
spec interpretation regarding the layout of the _FIT vs. NFIT
tables.  In addition to changing the code, we are proposing
wording changes to the ACPI spec.

While testing the notify code path, I discovered that the 
way the old and new tables were compared didn't take into account
that there is some variation in table length.  I also determined
that the check for whether the NFIT merge was successful was
backwards.

I couldn't find a generic way to invoke the notify function
so my testing was done with a change to the the revision_show()
function that calls acpi_nfit_notify() any time the sysfs
nfit/revision file is read.  That change is not included here.

These patches were tested on a system with NVDIMM-N hardware
so changes related to NFIT tables not provided on a NVDIMM-N
system have only been compile-tested.  

Linda Knippers (3):
  nfit: Account for table size length variation
  nfit: Fix the check for a successful NFIT merge
  nfit: Adjust for different _FIT and NFIT headers

 drivers/acpi/nfit.c | 83 +++++++++++++++++++++++++++++++++++++++++------------
 drivers/acpi/nfit.h |  3 +-
 2 files changed, 67 insertions(+), 19 deletions(-)

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1.8.3.1