From: Pavel Machek <pavel@suse.cz>
Date: Wed, 26 Nov 2008 16:15:21 +0000 (+0100)
Subject: Document handling of bad memory
X-Git-Tag: v2.6.29-rc1~43^2~1
X-Git-Url: http://pilppa.com/gitweb/?a=commitdiff_plain;h=2884f00b94be73a6a7875bada739bf9bb2f9a1b6;p=linux-2.6-omap-h63xx.git

Document handling of bad memory

Document how to deal with bad memory reported with memtest.

Signed-off-by: Jan-Simon Möller <dl9pf@gmx.de>
Signed-off-by: Pavel Machek <pavel@suse.cz>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
---

diff --git a/Documentation/bad_memory.txt b/Documentation/bad_memory.txt
new file mode 100644
index 00000000000..df841621320
--- /dev/null
+++ b/Documentation/bad_memory.txt
@@ -0,0 +1,45 @@
+March 2008
+Jan-Simon Moeller, dl9pf@gmx.de
+
+
+How to deal with bad memory e.g. reported by memtest86+ ?
+#########################################################
+
+There are three possibilities I know of:
+
+1) Reinsert/swap the memory modules
+
+2) Buy new modules (best!) or try to exchange the memory
+   if you have spare-parts
+
+3) Use BadRAM or memmap
+
+This Howto is about number 3) .
+
+
+BadRAM
+######
+BadRAM is the actively developed and available as kernel-patch
+here:  http://rick.vanrein.org/linux/badram/
+
+For more details see the BadRAM documentation.
+
+memmap
+######
+
+memmap is already in the kernel and usable as kernel-parameter at
+boot-time.  Its syntax is slightly strange and you may need to
+calculate the values by yourself!
+
+Syntax to exclude a memory area (see kernel-parameters.txt for details):
+memmap=<size>$<address>
+
+Example: memtest86+ reported here errors at address 0x18691458, 0x18698424 and
+         some others. All had 0x1869xxxx in common, so I chose a pattern of
+         0x18690000,0xffff0000.
+
+With the numbers of the example above:
+memmap=64K$0x18690000
+ or
+memmap=0x10000$0x18690000
+