diff options
Diffstat (limited to 'Documentation/rtc.txt')
| -rw-r--r-- | Documentation/rtc.txt | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/Documentation/rtc.txt b/Documentation/rtc.txt index 95d17b3e2eee..2a58f985795a 100644 --- a/Documentation/rtc.txt +++ b/Documentation/rtc.txt | |||
| @@ -44,8 +44,10 @@ normal timer interrupt, which is 100Hz. | |||
| 44 | Programming and/or enabling interrupt frequencies greater than 64Hz is | 44 | Programming and/or enabling interrupt frequencies greater than 64Hz is |
| 45 | only allowed by root. This is perhaps a bit conservative, but we don't want | 45 | only allowed by root. This is perhaps a bit conservative, but we don't want |
| 46 | an evil user generating lots of IRQs on a slow 386sx-16, where it might have | 46 | an evil user generating lots of IRQs on a slow 386sx-16, where it might have |
| 47 | a negative impact on performance. Note that the interrupt handler is only | 47 | a negative impact on performance. This 64Hz limit can be changed by writing |
| 48 | a few lines of code to minimize any possibility of this effect. | 48 | a different value to /proc/sys/dev/rtc/max-user-freq. Note that the |
| 49 | interrupt handler is only a few lines of code to minimize any possibility | ||
| 50 | of this effect. | ||
| 49 | 51 | ||
| 50 | Also, if the kernel time is synchronized with an external source, the | 52 | Also, if the kernel time is synchronized with an external source, the |
| 51 | kernel will write the time back to the CMOS clock every 11 minutes. In | 53 | kernel will write the time back to the CMOS clock every 11 minutes. In |
| @@ -81,6 +83,7 @@ that will be using this driver. | |||
| 81 | */ | 83 | */ |
| 82 | 84 | ||
| 83 | #include <stdio.h> | 85 | #include <stdio.h> |
| 86 | #include <stdlib.h> | ||
| 84 | #include <linux/rtc.h> | 87 | #include <linux/rtc.h> |
| 85 | #include <sys/ioctl.h> | 88 | #include <sys/ioctl.h> |
| 86 | #include <sys/time.h> | 89 | #include <sys/time.h> |