Re: Detecting ichlpcib watchdog "NO_REBOOT" state

[Matt Thomas <matt%3am-software.com@localhost>]

On Jun 4, 2011, at 9:05 PM, Thor Lancelot Simon wrote:

> On Sat, Jun 04, 2011 at 11:25:16PM +0200, Joerg Sonnenberger wrote:
>> On Sat, Jun 04, 2011 at 11:01:09AM -0500, David Young wrote:
>>> I agree with Thor on "principle of least surprise" grounds:  NetBSD
>>> shouldn't attach the watchdog that will not actually reboot the system.
>> 
>> Having the watchdog still allows you to enter DDB. Think one step ahead:
>> certain ICH6 generations can't reboot the system, but are not detectable
>> by software. The Thinkpad R52 had that problem. Either the watchdog API
>> should allow to specify what types of watch dog actions are (not)
>> possible or it needs to be exported via side channel. The functionality
>> of the hardware is still useful.
> 
> It's not the same semantics as any other known watchdog.
> 
> Semantic confusion benefits nobody.  Until the watchdog code can
> express a "does something useful but doesn't reboot the system"
> watchdog, it should be disabled by default.

Well, for mpc85xx, the watchdog will cause a panic which enters ddb if sysctl 
allows it.  If nothing is done, the system will reset in the next watchdog 
interval.