linux/Documentation/bad_memory.txt
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   1March 2008
   2Jan-Simon Moeller, dl9pf@gmx.de
   3
   4
   5How to deal with bad memory e.g. reported by memtest86+ ?
   6#########################################################
   7
   8There are three possibilities I know of:
   9
  101) Reinsert/swap the memory modules
  11
  122) Buy new modules (best!) or try to exchange the memory
  13   if you have spare-parts
  14
  153) Use BadRAM or memmap
  16
  17This Howto is about number 3) .
  18
  19
  20BadRAM
  21######
  22BadRAM is the actively developed and available as kernel-patch
  23here:  http://rick.vanrein.org/linux/badram/
  24
  25For more details see the BadRAM documentation.
  26
  27memmap
  28######
  29
  30memmap is already in the kernel and usable as kernel-parameter at
  31boot-time.  Its syntax is slightly strange and you may need to
  32calculate the values by yourself!
  33
  34Syntax to exclude a memory area (see kernel-parameters.txt for details):
  35memmap=<size>$<address>
  36
  37Example: memtest86+ reported here errors at address 0x18691458, 0x18698424 and
  38         some others. All had 0x1869xxxx in common, so I chose a pattern of
  39         0x18690000,0xffff0000.
  40
  41With the numbers of the example above:
  42memmap=64K$0x18690000
  43 or
  44memmap=0x10000$0x18690000
  45
  46