[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>
diff --git a/Documentation/fb/vesafb.txt b/Documentation/fb/vesafb.txt
index 814e2f5..62db675 100644
--- a/Documentation/fb/vesafb.txt
+++ b/Documentation/fb/vesafb.txt
@@ -144,7 +144,21 @@
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