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Date: Tue, 5 Apr 2011 21:45:48 +0100
Message-ID: <BANLkTi=852nKvBOJL1DrkDG3Sh_04q4=JA@mail.gmail.com>
Subject: Re: [Qemu-devel] Questions about chardev (and ps/2 mouse)
From: Peter Maydell <peter.maydell@linaro.org>
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To: Anthony Liguori <anthony@codemonkey.ws>
Cc: qemu-devel@nongnu.org

On 5 April 2011 21:29, Anthony Liguori <anthony@codemonkey.ws> wrote:
> On 04/05/2011 01:55 PM, Brian Wheeler wrote:
>>
>> I'm trying to disable the ps/2 mouse in favor of the serial mouse
>> provided by -chardev msmouse since the ps/2 mouse has had lots of
>> problems with older OSes (OpenStep, OS/2, Win 3.1, etc). =C2=A0I've got =
a
>> couple of questions:
>>
>> 1) If I change a VMState something by appending a field (i.e.
>> "unplugged"), do I have to update version_id?
>
> Yes. =C2=A0You can use a subsection though to avoid bumping the version_i=
d.
>
>> =C2=A0 How do the
>> minimum_version_id{,_old} fields fit in?
>
> This is for load, not save. =C2=A0It's used to basically deprecate loadin=
g from
> very old versions.

There was an email thread about this recently:
http://web.archiveorange.com/archive/v/1XS1vynR1fW0cG5xll6r

I need to go back and reread it and propose a docs patch
for people to shoot down; I think having a clear description
of "what do I have to do if I've added a new field to a device
model" is important, because that will often be the only
interaction a developer has with the migration/vmstate stuff.

-- PMM