Hardware Watchdog Device in pSeries?

Alan Robertson alanr at unix.sh
Fri Oct 15 01:56:14 EST 2004

Arnd Bergmann wrote:
> On Middeweken 13 Oktober 2004 21:23, Linas Vepstas wrote:
>>On Wed, Oct 13, 2004 at 12:01:45PM -0600, Alan Robertson was heard to remark:
>>>This would be a logical equivalent to the well-known and long-standing 
>>>'softdog' device driver which already has a well-known API, which is also 
>>>implemented on other hardware devices and architectures.
>>>So, my suggestion would be that if it were moved to a userspace driver, 
>>>that the softdog API be retained.
>>I might have volunteered to hack this up real quick, were it not for
>>Mike Strosaker's correction, that the surveillance featues were taken
>>out of Power5.   
> FWIW, s390 linux has just added support for a hypervisor watchdog [1]
> that looks like a hardware watchdog to linux, but is implemented with
> hypercalls ("diag 0x288"). Since Power5 is typically running in hypervisor
> more, the watchdog interface could be provided completely by the
> firmware.

The method of implementation isn't that important.  Are these hypervisor 
calls (or equivalent) provided by power5?

Is there any disadvantage to running under the hypervisor?

     Alan Robertson <alanr at unix.sh>

"Openness is the foundation and preservative of friendship...  Let me claim 
from you at all times your undisguised opinions." - William Wilberforce

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