On 09/10/2014 11:26 AM, Andy Lutomirski wrote:
> On Wed, Sep 10, 2014 at 9:51 AM, Toshi Kani <[email protected]> wrote:
>> This patch changes reserve_memtype() to handle the WT cache mode.
>> When PAT is not enabled, it continues to set UC- to *new_type for
>> any non-WB request.
>>
>> When a target range is RAM, reserve_ram_pages_type() fails for WT
>> for now. This function may not reserve a RAM range for WT since
>> reserve_ram_pages_type() uses the page flags limited to three memory
>> types, WB, WC and UC.
>
> Should it fail if WT is unavailable due to errata? More generally,
> how are all of the do_something_wc / do_something_wt /
> do_something_nocache helpers supposed to handle unsupported types?
>
Errata, or because it is pre-PAT hardware. Keep in mind that even
pre-PAT hardware supports using page tables for cache types, it is only
that the only types supposed are WB, WT, UC.
-hpa
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