From mboxrd@z Thu Jan  1 00:00:00 1970
From: erik quanstrom <quanstro@coraid.com>
Date: Tue, 14 Jul 2009 12:49:47 -0400
To: 9fans@9fans.net
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Subject: Re: [9fans] ugliness in vesa
Topicbox-Message-UUID: 204fcb3c-ead5-11e9-9d60-3106f5b1d025

> As I'm reading it, the change to vganvidia.c you posted above
> (re-pasted below) does pat stuff. Am I confused? I don't think pat and
> mtrr are the same thing...

they're not.  mtrr operates at the physical address level and
it's just a bunch of registers that control caching of a (limited set of)
fixed and variable ranges.  pat on the other hand, works on
page tables (and directories).

however the net result is that for pci space (or the vga ap)
which is normally UC (or is it UC-), if you use a mtrr range to
mark it as WT or pat entries to market it as WT, there is no
difference.

- erik