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-rw-r--r--include/linux/delay.h11
1 files changed, 11 insertions, 0 deletions
diff --git a/include/linux/delay.h b/include/linux/delay.h
index a6ecb34cf547..2ecb3c46b20a 100644
--- a/include/linux/delay.h
+++ b/include/linux/delay.h
@@ -5,6 +5,17 @@
* Copyright (C) 1993 Linus Torvalds
*
* Delay routines, using a pre-computed "loops_per_jiffy" value.
+ *
+ * Please note that ndelay(), udelay() and mdelay() may return early for
+ * several reasons:
+ * 1. computed loops_per_jiffy too low (due to the time taken to
+ * execute the timer interrupt.)
+ * 2. cache behaviour affecting the time it takes to execute the
+ * loop function.
+ * 3. CPU clock rate changes.
+ *
+ * Please see this thread:
+ * http://lists.openwall.net/linux-kernel/2011/01/09/56
*/
#include <linux/kernel.h>