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From: Gerd Hoffmann <kraxel@redhat.com>
Date: Wed, 01 Nov 2017 08:58:32 +0100
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Subject: Re: [Qemu-devel] [PULL 4/9] ps2: fix scancodes sent for Alt-Print
 key combination (aka SysRq)
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To: "Daniel P. Berrange" <berrange@redhat.com>
Cc: qemu-devel@nongnu.org

  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.

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.

cheers,
  Gerd