Re: [Linux-nvdimm] [PATCH v2 11/20] libnd, nd_pmem: add libnd support to the pmem driver

[Andy Lutomirski]

On Wed, Apr 29, 2015 at 8:55 AM, Dan Williams <dan.j.williams@xxxxxxxxx> wrote:
> On Tue, Apr 28, 2015 at 3:58 PM, Andy Lutomirski <luto@xxxxxxxxxxxxxx> wrote:
>> On Tue, Apr 28, 2015 at 3:21 PM, Phil Pokorny
>> <ppokorny@xxxxxxxxxxxxxxxxxxxx> wrote:
>>> On Tue, Apr 28, 2015 at 2:04 PM, Andy Lutomirski <luto@xxxxxxxxxxxxxx> wrote:
>>>> On Tue, Apr 28, 2015 at 11:25 AM, Dan Williams <dan.j.williams@xxxxxxxxx> wrote:
> [..]
>> This is such a mess that I think this driver should maybe flat-out
>> refuse to load in this type of configuration without some scary module
>> option.  I have some NVDIMMs that report as type 12 but need two extra
>> out-of-tree drivers to work safely.  First, they need i2c_imc or the
>> equivalent (I'll try to resubmit that soon).  Second, they need secret
>> magic NDAed register poking.  The latter is very problematic.
>>
>> At the very least, I think we should discourage people who don't
>> really know what they're doing from using this driver without care.
>
> The benefit of the type-12 experiment having not made it very far out
> of the lab is that it may be feasible to whitelist known platforms
> where we believe ADR is available.  Otherwise, the presence of the
> NFIT asserts platform persistent memory support.

This could be a good idea.  I'm planning on resubmitting my i2c driver
in the next couple weeks, and maybe I'll whitelist my own platform :)

--Andy

-- 
Andy Lutomirski
AMA Capital Management, LLC
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