Re: [Qemu-devel] [PATCH v3] hw/i386: Deprecate the machines pc-0.10 to pc-1.2

[Eduardo Habkost]

On Wed, Jul 12, 2017 at 04:04:00PM +0100, Daniel P. Berrange wrote:
> On Wed, Jul 12, 2017 at 10:22:33AM +0200, Thomas Huth wrote:
> > We don't want to carry along old machine types forever. If we are able to
> > remove the pc machines up to 0.13 one day for example, this would allow
> > us to eventually kill the code for rombar=0 (i.e. where QEMU copies ROM
> > BARs directly to low memory). Everything up to pc-1.2 is also known to
> > have issues with migration.  So let's start with a deprecation message
> > for the old machine types so that the (hopefully) few users of these old
> > systems start switching over to newer machine types instead.
> 
> I think we must document & agree on our support policy for machine
> types, before we start marking them as deprecated. eg please consider
> the following document before accepting this deprecation patch:
> 
>  https://lists.gnu.org/archive/html/qemu-devel/2017-07/msg00652.html
> 
> Note in that proposal there, I say we do *not* go through trouble of
> explicitly marking machines as deprecated. We just document upfront
> the intended lifecycle and then delete them when it is done.
> 
> Just use deprecation warnings for things where there is no predictable
> lifecycle upfront.

I'd bet most people won't read the deprecation policy
documentation, and a deprecation warning for 1 or 2 releases
would be still useful before we finally remove a machine-type.

-- 
Eduardo