Re: [Qemu-devel] [PULL 4/9] ps2: fix scancodes sent for Alt-Print key combination (aka SysRq)

[Daniel P. Berrange]

On Wed, Nov 01, 2017 at 08:58:32AM +0100, Gerd Hoffmann wrote:
>   Hi,
> 
> > No one confirmed whether or not this new field needs to be added to
> > the
> > VMSTATE sections, and if so, how todo this in a back compatible
> > manner....
> 
> Good question.  Sky isn't falling if we don't send this over, worst
> case is a minor keyboard glitch, affecting only the SysRq key, right?
> 
> Annoying things like sticky modifier keys should not happen.  So I'd
> tend to simply leave things as-is.

Yeah, we would only gitch that key combo. It should be (practically) impossible
to hit, because from the user input POV its just a single key, that internally
we turn into a sequence of keys when injecting.

> 
> When sending it over we need a subsection for it.  Simplest way would
> be to only send over the section in the unlikely case that the field is
> non-zero.  But this might fail migration to older qemu versions in case
> someone hits a modifier key the wrong moment.  Alternatively send the
> sibsection only on new machine types using a compat property, but that
> needs a bit more boilerplate.

Regards,
Daniel
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