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Diffstat (limited to 'Documentation/mtrr.txt')
| -rw-r--r-- | Documentation/mtrr.txt | 17 |
1 files changed, 17 insertions, 0 deletions
diff --git a/Documentation/mtrr.txt b/Documentation/mtrr.txt index 4b6264bcd..af58d63d7 100644 --- a/Documentation/mtrr.txt +++ b/Documentation/mtrr.txt @@ -62,6 +62,23 @@ in other words the X server will manipulate /proc/mtrr using the ioctl() interface, so users won't have to do anything. If you use a commercial X server, lobby your vendor to add support for MTRRs. =============================================================================== +Creating overlapping MTRRs: + +%echo "base=0xfb000000 size=0x1000000 type=write-combining" >/proc/mtrr +%echo "base=0xfb000000 size=0x1000 type=uncachable" >/proc/mtrr + +And the results: cat /proc/mtrr +reg00: base=0x00000000 ( 0MB), size= 64MB: write-back, count=1 +reg01: base=0xfb000000 (4016MB), size= 16MB: write-combining, count=1 +reg02: base=0xfb000000 (4016MB), size= 4kB: uncachable, count=1 + +Some cards (especially Voodoo Graphics boards) need this 4 kB area +excluded from the beginning of the region because it is used for +registers. + +NOTE: You can only create type=uncachable region, if the first +region that you created is type=write-combining. +=============================================================================== Removing MTRRs from the shell: % echo "disable=2" >! /proc/mtrr =============================================================================== |