Re: [Qemu-devel] -vga std vs. -device VGA

[Alexey Kardashevskiy <aik@ozlabs.ru>]

On 11/15/2013 10:03 AM, Peter Maydell wrote:
> On 14 November 2013 22:32, Benjamin Herrenschmidt
> <benh@kernel.crashing.org> wrote:
>> On Thu, 2013-11-14 at 17:23 -0500, Alexander Graf wrote:
>>> Yes. But I think it's the correct thing to do in this case. X86 also
>>> doesn't create a USB controller like we would have to. Our pseries
>>> platform just doesn't have a legacy PC/AT keyboard controller.
>>
>> Sure, but that implies that -nodefaults -device VGA creates a working
>> usable machine on x86 and not on pseries...
> 
> Sounds plausible. Anything using -nodefaults has to have
> knowledge of every QEMU machine type it wants to use
> so it can know which devices need adding in order to get
> various functionality. ('-device VGA' doesn't work at all on
> some, for instance). If you ask for full manual control, you
> get full manual control :-)

That is ok and I asked our libvirt person to fix it (Hi Li :) ).

What I still do not completely understand is the principle used about
automatic device creation. Specifically, "-device VGA" creates only VGA
(and that is understandable) but "-vga std" creates more devices, if if
used together with "-nodefaults".

Is it because "-device" must create only what it is told to create and
others non-"-device" options (-usb? -vga? -machine ...? any!) can
auto-create whatever they want (well, what seems reasonable to create for
the specific arch)?


-- 
Alexey