Fwd: ls_sensors, fscscy.o & watchdog

Arpi arpi at thot.banki.hu
Tue Jun 3 17:15:36 CEST 2003

original recipent's server bounced it back :(

--------- Forwarded message ---------
From: Arpi <arpi at thot.banki.hu>
To: mkn at teraport.de
Subject: ls_sensors, fscscy.o & watchdog


I've spent few hours experiencing with the watchdog feature of the Fujitsu
Siemens server board (don't ask the model name, what i know is that it uses
serverworks CSB5 chipset) using lm_sensors 2.7.0's fscscy driver.
(I needed it because i have random hangup (once a week, so hard to debug...)
on a server).

Ok, so there is /proc/sys/dev/sensors/fscscy-i2c-0-73/wdog, containing 3
0..255 values for the 3 watchdog registers.

The first one is the time counter, it counts backwards (seems write-only,
at least you can't read the current counter back). It's in 2 seconds base,
so writting 30 there means 60 seconds delay. It seems whole 0..255 range is
supported, so up to 510 seconds. writting 0 means immediate hardware reset.
The second number is unknown to me, it doesn't matter what value i put there.
The third is the control register, with flags 16, 32 and 128.
If i write only 16 or 144 (128+16), it means system reset when the counter
reaches 0. If i OR 32, it has no effect.

So, the world's simples watchdog using this mainboard:

while true ; do
  echo 30 0 16 > /proc/sys/dev/sensors/fscscy-i2c-0-73/wdog
  sleep 10

it does hardware reset after 1 minutes, if this script is killed or system
hangup occurs.

Also note, that BIOS has a strange setting, named OS Boot Retry Count, set
to 0 by default, it changes watchdog behaviour to power off instead of reset.
(0=poweroff 1..7=reset). It took me a while to find this...

Please add the above to the documentation (doc/chips/fscscy), so i can save
a few hours of resetting for other people :)

A'rpi / Astral & ESP-team

Developer of MPlayer G2, the Movie Framework for all - http://www.MPlayerHQ.hu

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