Commit 9be05b57 authored by Jean Delvare's avatar Jean Delvare Committed by Linus Torvalds

[PATCH] rtc: small documentation update

Rtc driver documentation update

* Mention the max-user-freq control file.
* Add missing header in example code.
Signed-off-by: default avatarJean Delvare <khali@linux-fr.org>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 8e12ecc2
......@@ -44,8 +44,10 @@ normal timer interrupt, which is 100Hz.
Programming and/or enabling interrupt frequencies greater than 64Hz is
only allowed by root. This is perhaps a bit conservative, but we don't want
an evil user generating lots of IRQs on a slow 386sx-16, where it might have
a negative impact on performance. Note that the interrupt handler is only
a few lines of code to minimize any possibility of this effect.
a negative impact on performance. This 64Hz limit can be changed by writing
a different value to /proc/sys/dev/rtc/max-user-freq. Note that the
interrupt handler is only a few lines of code to minimize any possibility
of this effect.
Also, if the kernel time is synchronized with an external source, the
kernel will write the time back to the CMOS clock every 11 minutes. In
......@@ -81,6 +83,7 @@ that will be using this driver.
*/
#include <stdio.h>
#include <stdlib.h>
#include <linux/rtc.h>
#include <sys/ioctl.h>
#include <sys/time.h>
......
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment