Re: [PATCH 0/4] hw: make TCO watchdog actually work by default for Q35

[Igor Mammedov]

On Mon, 31 Oct 2022 11:48:58 -0400
"Michael S. Tsirkin" <mst@redhat.com> wrote:

> On Mon, Oct 31, 2022 at 01:50:24PM +0000, Daniel P. Berrangé wrote:
> > On Mon, Oct 31, 2022 at 01:19:30PM +0000, Daniel P. Berrangé wrote:  
> > > The TCO watchdog is unconditionally integrated into the Q35 machine
> > > type by default, but at the same time is unconditionally disabled
> > > from firing by a host config option that overrides guest OS attempts
> > > to enable it. People have to know to set a magic -global to make
> > > it non-broken  
> > 
> > Incidentally I found that originally the TCO watchdog was not
> > unconditionally enabled. Its exposure to the guest could be
> > turned on/off using
> > 
> >   -global ICH9-LPC.enable_tco=bool
> > 
> > This was implemented for machine type compat, but it also gave
> > apps a way to disable the watchdog functionality. Unfortunately
> > that ability was discarded in this series:
> > 
> >   
> > https://lore.kernel.org/all/1453564933-29638-1-git-send-email-ehabkost@redhat.com/
> > 
> > but the 'enable_tco' property still exists in QOM, but silently
> > ignored.
> > 
> > Seems we should either fix the impl of 'enable_tco', or remove the
> > QOM property entirely, so we don't pretend it can be toggled anymore.
> > 
> > With regards,
> > Daniel  
> 
> i am inclined to say you are right and the fix is to fix the impl.

Is there need for users to disable whatchdog at all?
It was always present since then and no one complained, 
so perhaps we should ditch property instead fixing it
to keep it simple.

> 
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