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Diffstat (limited to 'Documentation/watchdog/watchdog-api.txt')
| -rw-r--r-- | Documentation/watchdog/watchdog-api.txt | 30 |
1 files changed, 29 insertions, 1 deletions
diff --git a/Documentation/watchdog/watchdog-api.txt b/Documentation/watchdog/watchdog-api.txt index 21ed5117366..7dc2c1c6f77 100644 --- a/Documentation/watchdog/watchdog-api.txt +++ b/Documentation/watchdog/watchdog-api.txt @@ -110,7 +110,31 @@ current timeout using the GETTIMEOUT ioctl. ioctl(fd, WDIOC_GETTIMEOUT, &timeout); printf("The timeout was is %d seconds\n", timeout); -Envinronmental monitoring: +Pretimeouts: + +Some watchdog timers can be set to have a trigger go off before the +actual time they will reset the system. This can be done with an NMI, +interrupt, or other mechanism. This allows Linux to record useful +information (like panic information and kernel coredumps) before it +resets. + + pretimeout = 10; + ioctl(fd, WDIOC_SETPRETIMEOUT, &pretimeout); + +Note that the pretimeout is the number of seconds before the time +when the timeout will go off. It is not the number of seconds until +the pretimeout. So, for instance, if you set the timeout to 60 seconds +and the pretimeout to 10 seconds, the pretimout will go of in 50 +seconds. Setting a pretimeout to zero disables it. + +There is also a get function for getting the pretimeout: + + ioctl(fd, WDIOC_GETPRETIMEOUT, &timeout); + printf("The pretimeout was is %d seconds\n", timeout); + +Not all watchdog drivers will support a pretimeout. + +Environmental monitoring: All watchdog drivers are required return more information about the system, some do temperature, fan and power level monitoring, some can tell you @@ -169,6 +193,10 @@ The watchdog saw a keepalive ping since it was last queried. WDIOF_SETTIMEOUT Can set/get the timeout +The watchdog can do pretimeouts. + + WDIOF_PRETIMEOUT Pretimeout (in seconds), get/set + For those drivers that return any bits set in the option field, the GETSTATUS and GETBOOTSTATUS ioctls can be used to ask for the current |