ipmi watchdog : add panic_wdt_timeout parameter

In order to allow panic actions to be processed, the ipmi watchdog
driver sets a new timeout value on panic. The 255s timeout
was designed to allow kdump and others actions on panic, as in
http://lkml.iu.edu/hypermail/linux/kernel/0711.3/0258.html

This is counter-intuitive for a end-user who sets watchdog timeout
value to something like 30s and who expects BMC to reset the system
within 30s of a panic.

This commit allows user to configure the timeout on panic.
Signed-off-by: Jean-Yves Faye <jean-yves.faye@c-s.fr>
Signed-off-by: Corey Minyard <cminyard@mvista.com>

Documentation/IPMI.txt

@@ -587,7 +587,7 @@ used to control it:
 
   modprobe ipmi_watchdog timeout=<t> pretimeout=<t> action=<action type>
       preaction=<preaction type> preop=<preop type> start_now=x
-      nowayout=x ifnum_to_use=n
+      nowayout=x ifnum_to_use=n panic_wdt_timeout=<t>
 
 ifnum_to_use specifies which interface the watchdog timer should use.
 The default is -1, which means to pick the first one registered.
@@ -597,7 +597,9 @@ is the amount of seconds before the reset that the pre-timeout panic will
 occur (if pretimeout is zero, then pretimeout will not be enabled).  Note
 that the pretimeout is the time before the final timeout.  So if the
 timeout is 50 seconds and the pretimeout is 10 seconds, then the pretimeout
-will occur in 40 second (10 seconds before the timeout).
+will occur in 40 second (10 seconds before the timeout). The panic_wdt_timeout
+is the value of timeout which is set on kernel panic, in order to let actions
+such as kdump to occur during panic.
 
 The action may be "reset", "power_cycle", or "power_off", and
 specifies what to do when the timer times out, and defaults to
@@ -634,6 +636,7 @@ for configuring the watchdog:
 	ipmi_watchdog.preop=<preop type>
 	ipmi_watchdog.start_now=x
 	ipmi_watchdog.nowayout=x
+	ipmi_watchdog.panic_wdt_timeout=<t>
 
 The options are the same as the module parameter options.
 

drivers/char/ipmi/ipmi_watchdog.c

@@ -153,6 +153,9 @@ static int timeout = 10;
 /* The pre-timeout is disabled by default. */
 static int pretimeout;
 
+/* Default timeout to set on panic */
+static int panic_wdt_timeout = 255;
+
 /* Default action is to reset the board on a timeout. */
 static unsigned char action_val = WDOG_TIMEOUT_RESET;
 
@@ -293,6 +296,9 @@ MODULE_PARM_DESC(timeout, "Timeout value in seconds.");
 module_param(pretimeout, timeout, 0644);
 MODULE_PARM_DESC(pretimeout, "Pretimeout value in seconds.");
 
+module_param(panic_wdt_timeout, timeout, 0644);
+MODULE_PARM_DESC(timeout, "Timeout value on kernel panic in seconds.");
+
 module_param_cb(action, &param_ops_str, action_op, 0644);
 MODULE_PARM_DESC(action, "Timeout action. One of: "
 		 "reset, none, power_cycle, power_off.");
@@ -1189,7 +1195,7 @@ static int wdog_panic_handler(struct notifier_block *this,
 		/* Make sure we do this only once. */
 		panic_event_handled = 1;
 
-		timeout = 255;
+		timeout = panic_wdt_timeout;
 		pretimeout = 0;
 		panic_halt_ipmi_set_timeout();
 	}