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Random sampling of some URLs in the Documentation tree to see how many were stale found that one watchdog driver was now a porn site. In fact if the watchdogs document directory was any older it would be written in latin Clean it up somewhat and add Last reviewed headers, something all the Documentation could do with IMHO. Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
43 lines
1.5 KiB
Text
43 lines
1.5 KiB
Text
Last Reviewed: 10/05/2007
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WDT Watchdog Timer Interfaces For The Linux Operating System
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Alan Cox <alan@lxorguk.ukuu.org.uk>
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ICS WDT501-P
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ICS WDT501-P (no fan tachometer)
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ICS WDT500-P
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All the interfaces provide /dev/watchdog, which when open must be written
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to within a timeout or the machine will reboot. Each write delays the reboot
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time another timeout. In the case of the software watchdog the ability to
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reboot will depend on the state of the machines and interrupts. The hardware
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boards physically pull the machine down off their own onboard timers and
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will reboot from almost anything.
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A second temperature monitoring interface is available on the WDT501P cards
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This provides /dev/temperature. This is the machine internal temperature in
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degrees Fahrenheit. Each read returns a single byte giving the temperature.
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The third interface logs kernel messages on additional alert events.
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The wdt card cannot be safely probed for. Instead you need to pass
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wdt=ioaddr,irq as a boot parameter - eg "wdt=0x240,11".
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Features
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--------
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WDT501P WDT500P
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Reboot Timer X X
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External Reboot X X
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I/O Port Monitor o o
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Temperature X o
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Fan Speed X o
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Power Under X o
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Power Over X o
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Overheat X o
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The external event interfaces on the WDT boards are not currently supported.
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Minor numbers are however allocated for it.
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Example Watchdog Driver: see Documentation/watchdog/src/watchdog-simple.c
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