mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-11-01 00:48:50 +00:00
cc2a2d19f8
Convert those documents and prepare them to be part of the kernel API book, as most of the stuff there are related to the Kernel interfaces. Still, in the future, it would make sense to split the docs, as some of the stuff is clearly focused on sysadmin tasks. The conversion is actually: - add blank lines and identation in order to identify paragraphs; - fix tables markups; - add some lists markups; - mark literal blocks; - adjust title markups. At its new index.rst, let's add a :orphan: while this is not linked to the main index.rst file, in order to avoid build warnings. Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org> Reviewed-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Jonathan Corbet <corbet@lwn.net>
63 lines
2.1 KiB
ReStructuredText
63 lines
2.1 KiB
ReStructuredText
============================================================
|
|
WDT Watchdog Timer Interfaces For The Linux Operating System
|
|
============================================================
|
|
|
|
Last Reviewed: 10/05/2007
|
|
|
|
Alan Cox <alan@lxorguk.ukuu.org.uk>
|
|
|
|
- ICS WDT501-P
|
|
- ICS WDT501-P (no fan tachometer)
|
|
- ICS WDT500-P
|
|
|
|
All the interfaces provide /dev/watchdog, which when open must be written
|
|
to within a timeout or the machine will reboot. Each write delays the reboot
|
|
time another timeout. In the case of the software watchdog the ability to
|
|
reboot will depend on the state of the machines and interrupts. The hardware
|
|
boards physically pull the machine down off their own onboard timers and
|
|
will reboot from almost anything.
|
|
|
|
A second temperature monitoring interface is available on the WDT501P cards.
|
|
This provides /dev/temperature. This is the machine internal temperature in
|
|
degrees Fahrenheit. Each read returns a single byte giving the temperature.
|
|
|
|
The third interface logs kernel messages on additional alert events.
|
|
|
|
The ICS ISA-bus wdt card cannot be safely probed for. Instead you need to
|
|
pass IO address and IRQ boot parameters. E.g.::
|
|
|
|
wdt.io=0x240 wdt.irq=11
|
|
|
|
Other "wdt" driver parameters are:
|
|
|
|
=========== ======================================================
|
|
heartbeat Watchdog heartbeat in seconds (default 60)
|
|
nowayout Watchdog cannot be stopped once started (kernel
|
|
build parameter)
|
|
tachometer WDT501-P Fan Tachometer support (0=disable, default=0)
|
|
type WDT501-P Card type (500 or 501, default=500)
|
|
=========== ======================================================
|
|
|
|
Features
|
|
--------
|
|
|
|
================ ======= =======
|
|
WDT501P WDT500P
|
|
================ ======= =======
|
|
Reboot Timer X X
|
|
External Reboot X X
|
|
I/O Port Monitor o o
|
|
Temperature X o
|
|
Fan Speed X o
|
|
Power Under X o
|
|
Power Over X o
|
|
Overheat X o
|
|
================ ======= =======
|
|
|
|
The external event interfaces on the WDT boards are not currently supported.
|
|
Minor numbers are however allocated for it.
|
|
|
|
|
|
Example Watchdog Driver:
|
|
|
|
see samples/watchdog/watchdog-simple.c
|