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author | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2008-01-18 14:06:19 -0800 |
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committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2008-01-18 14:06:19 -0800 |
commit | c9daa2722a3f1967e3e9750fd4cb6a7352a3cd63 (patch) | |
tree | a28c40b8e4f8ee1d653d5add903e03a9be0ede8a | |
parent | 977c8fa4d75d4ebe7ebbe116eed9e06f780fb34d (diff) | |
parent | 0d710cba3afde2109030254ee90654fbb580e8af (diff) | |
download | kernel_samsung_smdk4412-c9daa2722a3f1967e3e9750fd4cb6a7352a3cd63.zip kernel_samsung_smdk4412-c9daa2722a3f1967e3e9750fd4cb6a7352a3cd63.tar.gz kernel_samsung_smdk4412-c9daa2722a3f1967e3e9750fd4cb6a7352a3cd63.tar.bz2 |
Merge git://git.kernel.org/pub/scm/linux/kernel/git/wim/linux-2.6-watchdog
* git://git.kernel.org/pub/scm/linux/kernel/git/wim/linux-2.6-watchdog:
[WATCHDOG] clarify watchdog operation in documentation
[WATCHDOG] Revert "Stop looking for device as soon as one is found"
-rw-r--r-- | Documentation/watchdog/watchdog-api.txt | 38 | ||||
-rw-r--r-- | drivers/watchdog/w83697hf_wdt.c | 4 |
2 files changed, 22 insertions, 20 deletions
diff --git a/Documentation/watchdog/watchdog-api.txt b/Documentation/watchdog/watchdog-api.txt index bb7cb1d..4cc4ba9 100644 --- a/Documentation/watchdog/watchdog-api.txt +++ b/Documentation/watchdog/watchdog-api.txt @@ -42,23 +42,27 @@ like this source file: see Documentation/watchdog/src/watchdog-simple.c A more advanced driver could for example check that a HTTP server is still responding before doing the write call to ping the watchdog. -When the device is closed, the watchdog is disabled. This is not -always such a good idea, since if there is a bug in the watchdog -daemon and it crashes the system will not reboot. Because of this, -some of the drivers support the configuration option "Disable watchdog -shutdown on close", CONFIG_WATCHDOG_NOWAYOUT. If it is set to Y when -compiling the kernel, there is no way of disabling the watchdog once -it has been started. So, if the watchdog daemon crashes, the system -will reboot after the timeout has passed. Watchdog devices also usually -support the nowayout module parameter so that this option can be controlled -at runtime. - -Drivers will not disable the watchdog, unless a specific magic character 'V' -has been sent /dev/watchdog just before closing the file. If the userspace -daemon closes the file without sending this special character, the driver -will assume that the daemon (and userspace in general) died, and will stop -pinging the watchdog without disabling it first. This will then cause a -reboot if the watchdog is not re-opened in sufficient time. +When the device is closed, the watchdog is disabled, unless the "Magic +Close" feature is supported (see below). This is not always such a +good idea, since if there is a bug in the watchdog daemon and it +crashes the system will not reboot. Because of this, some of the +drivers support the configuration option "Disable watchdog shutdown on +close", CONFIG_WATCHDOG_NOWAYOUT. If it is set to Y when compiling +the kernel, there is no way of disabling the watchdog once it has been +started. So, if the watchdog daemon crashes, the system will reboot +after the timeout has passed. Watchdog devices also usually support +the nowayout module parameter so that this option can be controlled at +runtime. + +Magic Close feature: + +If a driver supports "Magic Close", the driver will not disable the +watchdog unless a specific magic character 'V' has been sent to +/dev/watchdog just before closing the file. If the userspace daemon +closes the file without sending this special character, the driver +will assume that the daemon (and userspace in general) died, and will +stop pinging the watchdog without disabling it first. This will then +cause a reboot if the watchdog is not re-opened in sufficient time. The ioctl API: diff --git a/drivers/watchdog/w83697hf_wdt.c b/drivers/watchdog/w83697hf_wdt.c index 6ea125e..c622a0e 100644 --- a/drivers/watchdog/w83697hf_wdt.c +++ b/drivers/watchdog/w83697hf_wdt.c @@ -382,10 +382,8 @@ wdt_init(void) /* we will autodetect the W83697HF/HG watchdog */ for (i = 0; ((!found) && (w83697hf_ioports[i] != 0)); i++) { wdt_io = w83697hf_ioports[i]; - if (!w83697hf_check_wdt()) { + if (!w83697hf_check_wdt()) found++; - break; - } } } else { if (!w83697hf_check_wdt()) |