patch-1.3.98 linux/Documentation/rtc.txt

• Lines: 17
• Date: Tue Apr 30 12:48:50 1996
• Orig file: v1.3.97/linux/Documentation/rtc.txt
• Orig date: Mon Apr 15 12:20:16 1996

diff -u --recursive --new-file v1.3.97/linux/Documentation/rtc.txt linux/Documentation/rtc.txt
@@ -45,7 +45,15 @@
 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
-four lines of code to minimize any possibility of this effect.
+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 
+the process of doing this, the kernel briefly turns off RTC periodic 
+interrupts, so be aware of this if you are doing serious work. If you
+don't synchronize the kernel time with an external source (via ntp or
+whatever) then the kernel will keep its hands off the RTC, allowing you
+exclusive access to the device for your applications.
 
 The alarm and/or interrupt frequency are programmed into the RTC via
 various ioctl(2) calls as listed in ./include/linux/mc146818rtc.h