1. The doc entry mentions MmWriteCombined not a MmFrameBufferCached.
(Yes, I know they are defined to the same value in the _2K_ DDK. See
below).
2. That's 2K/XP help. I was asking about official support in Nt4.

P.S.
Eliyas,
When you see my questions on
microsoft.public.development.device.drivers, you can safely assume
that I already tried to look for answers at the obvious places like
various versions of DDK help, DDK include files and MSDN KB.

Posting the response I got from our engineer who owns memory management
subsystem:

It is the same as per the enum. We use the WriteCombined because this type
of mapping is applicable to things besides video frame buffers, and wanted
to make that more clear to other types of driver writers.

I don’t know if the writecombined mapping works on NT4 (I wouldn’t count on
it), especially when trying to do it via MTRRs because they have various
physical alignment and contiguity requirements as well. For win2000 and
above, we use the PAT mode of the processor to be able to provide these
mappings on a per-page basis and it should work well for the customer.


--
-Eliyas
This posting is provided "AS IS" with no warranties, and confers no rights.
http://www.microsoft.com/whdc/hwdev/driver/kb-drv.mspx