Re: [Linux-nvdimm] [PATCH 0/2] e820: Fix handling of NvDIMM chips

[Boaz Harrosh <boaz@plexistor.com>]

On 02/17/2015 12:03 AM, Matthew Wilcox wrote:
> On Mon, Feb 16, 2015 at 01:07:07PM +0200, Boaz Harrosh wrote:
>> In any way this is a problem for the new type-12 NvDIMM memory chips that
>> are circulating around. (It is estimated that there are already 100ds of
>> thousands NvDIMM chips in active use)
> 
> Hang on.  NV-DIMM chips don't know anyhing about E820 tables.  They don't
> have anything in them that says "I am type 12!".  How they are reported
> is up to the BIOS.  Just because your BIOS vendor has chosen to report
> tham as type 12 doesn't mean that any other BIOS vedor is going to have
> done the same thing.
> 
> Fortunately, the BIOS people have all got together and decided what
> they're going to do, and it's not type 12.  Unfortunately, I think
> I'm bound by various agreements to not say what they are going to do
> until they do.  But putting this temporary workaround in the kernel to
> accomodate one BIOS vendor's unreleased experimental code seems like
> entirely the wrong idea.
> 

I had a feeling I'm entering an holy war ;-).

I hope you are OK with my first patch. That an unknown type need not
be reported busy, and behave same as "reserved"?

Then if we agree about PATCH-1, which is the actual fix.
Then the 2nd patch (hence the RFC btw) is nothing more than
a name.

I have an old BIOS that knows nothing of NvDIMM, actually a few
of them they all report 12.
The fact of the matter is that all the people I've talked with,
reported that different vendor chips, all came up type-12.
Perhaps type-12 just means "Unknown to current BIOS"

What is the name you suggest "type-12" "unknown-12".
Do you understand why they all come out 12 ?

Thanks
Boaz