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docs: watchdog-api: general cleaning

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Correct some grammar, punctuation, and capitalization mistakes.

Drop extra words in printf() calls [likely a copy-paste error].

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Message-ID: <20260228010402.2389343-4-rdunlap@infradead.org>
This commit is contained in:
Randy Dunlap 2026-02-27 17:04:00 -08:00 committed by Jonathan Corbet
parent 996b4434be
commit 2a64c824d0
1 changed files with 20 additions and 18 deletions
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38
Documentation/watchdog/watchdog-api.rst
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@ -39,12 +39,12 @@ The simplest API
All drivers support the basic mode of operation, where the watchdog
activates as soon as /dev/watchdog is opened and will reboot unless
the watchdog is pinged within a certain time, this time is called the
the watchdog is pinged within a certain time; this time is called the
timeout or margin. The simplest way to ping the watchdog is to write
some data to the device. So a very simple watchdog daemon would look
like this source file: see samples/watchdog/watchdog-simple.c
A more advanced driver could for example check that a HTTP server is
A more advanced driver could for example check that an HTTP server is
still responding before doing the write call to ping the watchdog.
When the device is closed, the watchdog is disabled, unless the "Magic
@ -87,13 +87,13 @@ replaced with::
sleep(10);
}
the argument to the ioctl is ignored.
The argument to the ioctl is ignored.
Setting and getting the timeout
===============================
For some drivers it is possible to modify the watchdog timeout on the
fly with the SETTIMEOUT ioctl, those drivers have the WDIOF_SETTIMEOUT
fly with the SETTIMEOUT ioctl; those drivers have the WDIOF_SETTIMEOUT
flag set in their option field. The argument is an integer
representing the timeout in seconds. The driver returns the real
timeout used in the same variable, and this timeout might differ from
@ -110,7 +110,7 @@ Starting with the Linux 2.4.18 kernel, it is possible to query the
current timeout using the GETTIMEOUT ioctl::
ioctl(fd, WDIOC_GETTIMEOUT, &timeout);
printf("The timeout was is %d seconds\n", timeout);
printf("The timeout is %d seconds\n", timeout);
Pretimeouts
===========
@ -133,7 +133,7 @@ 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);
printf("The pretimeout is %d seconds\n", timeout);
Not all watchdog drivers will support a pretimeout.
@ -145,13 +145,13 @@ before the system will reboot. The WDIOC_GETTIMELEFT is the ioctl
that returns the number of seconds before reboot::
ioctl(fd, WDIOC_GETTIMELEFT, &timeleft);
printf("The timeout was is %d seconds\n", timeleft);
printf("The timeout is %d seconds\n", timeleft);
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
All watchdog drivers are required to return more information about the system.
Some do temperature, fan and power level monitoring; some can tell you
the reason for the last reboot of the system. The GETSUPPORT ioctl is
available to ask what the device can do::
@ -166,7 +166,7 @@ the fields returned in the ident struct are:
options a flags describing what the device supports
================ =============================================
the options field can have the following bits set, and describes what
The options field can have the following bits set, and describes what
kind of information that the GET_STATUS and GET_BOOT_STATUS ioctls can
return.
@ -175,13 +175,13 @@ return.
================ =========================
The machine was last rebooted by the watchdog because the thermal limit was
exceeded:
exceeded.
============== ==========
WDIOF_FANFAULT Fan failed
============== ==========
A system fan monitored by the watchdog card has failed
A system fan monitored by the watchdog card has failed.
============= ================
WDIOF_EXTERN1 External relay 1
@ -195,26 +195,26 @@ a reset.
WDIOF_EXTERN2 External relay 2
============= ================
External monitoring relay/source 2 was triggered
External monitoring relay/source 2 was triggered.
================ =====================
WDIOF_POWERUNDER Power bad/power fault
================ =====================
The machine is showing an undervoltage status
The machine is showing an undervoltage status.
=============== =============================
WDIOF_CARDRESET Card previously reset the CPU
=============== =============================
The last reboot was caused by the watchdog card
The last reboot was caused by the watchdog card.
================ =====================
WDIOF_POWEROVER Power over voltage
================ =====================
The machine is showing an overvoltage status. Note that if one level is
under and one over both bits will be set - this may seem odd but makes
under and one over, both bits will be set - this may seem odd but makes
sense.
=================== =====================
@ -227,12 +227,14 @@ The watchdog saw a keepalive ping since it was last queried.
WDIOF_SETTIMEOUT Can set/get the timeout
================ =======================
The watchdog can do pretimeouts.
The watchdog can get/set the timeout.
================ ================================
WDIOF_PRETIMEOUT Pretimeout (in seconds), get/set
================ ================================
The watchdog can do pretimeouts.
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
@ -255,7 +257,7 @@ returned value is the temperature in degrees Fahrenheit::
ioctl(fd, WDIOC_GETTEMP, &temperature);
Finally the SETOPTIONS ioctl can be used to control some aspects of
the cards operation::
the card's operation::
int options = 0;
ioctl(fd, WDIOC_SETOPTIONS, &options);