Re: [Qemu-devel] Questions about chardev (and ps/2 mouse)

[Peter Maydell <peter.maydell@linaro.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).  I'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.  You can use a subsection though to avoid bumping the version_id.
>
>>   How do the
>> minimum_version_id{,_old} fields fit in?
>
> This is for load, not save.  It's used to basically deprecate loading 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