From d7a465b4740806e4ee34061ad455595b2fa9fad5 Mon Sep 17 00:00:00 2001
From: "Antonino A. Daplas" <adaplas@gmail.com>
Date: Fri, 29 Jul 2005 22:59:21 -0700
Subject: [PATCH] [PATCH] vesafb: Document mtrr boot option usage

Document mtrr boot option usage to Documentation/fb/vesafb.txt.

Signed-off-by: Antonino Daplas <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
---
 Documentation/fb/vesafb.txt | 16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/Documentation/fb/vesafb.txt b/Documentation/fb/vesafb.txt
index 814e2f56a6ad..62db6758d1c1 100644
--- a/Documentation/fb/vesafb.txt
+++ b/Documentation/fb/vesafb.txt
@@ -144,7 +144,21 @@ vgapal	Use the standard vga registers for palette changes.
 	This is the default.
 pmipal	Use the protected mode interface for palette changes.
 
-mtrr	setup memory type range registers for the vesafb framebuffer.
+mtrr:n	setup memory type range registers for the vesafb framebuffer
+	where n:
+	      0 - disabled (equivalent to nomtrr)
+	      1 - uncachable
+	      2 - write-back
+	      3 - write-combining (default)
+	      4 - write-through
+
+	If you see the following in dmesg, choose the type that matches the
+	old one. In this example, use "mtrr:2".
+...
+mtrr: type mismatch for e0000000,8000000 old: write-back new: write-combining
+...
+
+nomtrr  disable mtrr
 
 vremap:n
         remap 'n' MiB of video RAM. If 0 or not specified, remap memory
-- 
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