x86/mm/mtrr, pat: Document Write Combining MTRR type effects on PAT / non-PAT pages

[karo-tx-linux.git] / arch / x86 / kernel / cpu / mtrr / main.c

diff --git a/arch/x86/kernel/cpu/mtrr/main.c b/arch/x86/kernel/cpu/mtrr/main.c
index ea5f363a194866303395358353a658750dcff3d4..04aceb7e6443d4790209037f7903198cd40aa9cc 100644 (file)
--- a/arch/x86/kernel/cpu/mtrr/main.c
+++ b/arch/x86/kernel/cpu/mtrr/main.c
@@ -538,6 +538,9 @@ EXPORT_SYMBOL(mtrr_del);
  * attempts to add a WC MTRR covering size bytes starting at base and
  * logs an error if this fails.
  *
+ * The called should provide a power of two size on an equivalent
+ * power of two boundary.
+ *
  * Drivers must store the return value to pass to mtrr_del_wc_if_needed,
  * but drivers should not try to interpret that return value.
  */