Re: [Qemu-devel] change x86 default machine type to Q35?

[Fam Zheng <famz@redhat.com>]

On Wed, 07/05 13:58, Thomas Huth wrote:
> On 05.07.2017 13:44, Fam Zheng wrote:
> > On Wed, 07/05 12:04, Daniel P. Berrange wrote:
> >> While you can say people should just add '-M pc' that isn't a nice
> >> user experiance, because it makes the assumption that people actually
> >> understand what caused their breakage. When the incompatibilities
> >> arise the error messages are unlikely to give any hint to users that
> >> the problems are caused by the machine type change. So unless someone
> >> is very familiar with debugging QEMU, they're not going to realize
> >> that '-M pc' will fix their problem.
> > 
> > While we change the default, can we start to print a message like 'machine type
> > ("-M" option) not specified, default to Q35. If you find compatibility issues,
> > try "-M pc"'?
> 
> Or we could simply remove the default machine type completely for a
> couple of releases? That would force people to update their script with
> "-M pc" ... and once this has been established, we can finally make q35
> the default?

I wouldn't do that.. Defaults are for those who don't care about setting it, or
want something that just works, by default. It's fine not to provide a default
machine type if we decide there isn't a clear win, just like arm, but IMHO
removing it just to restore it later in order to educate people makes a very
poor experience.

Fam