Re: [Qemu-devel] [RFC PATCH 2/2] Split fdd devices off the floppy controller

[Daniel P. Berrange]

On Mon, May 14, 2012 at 10:47:35AM +0200, Kevin Wolf wrote:
> Am 11.05.2012 17:22, schrieb Markus Armbruster:
> > For historical reasons, and unlike other block devices, our floppy
> > devices isa-fdc, sysbus-fdc and SUNW,fdtwo integrate the controller
> > and the drive(s) in a single qdev.  This makes them weird: we need
> > -global to set up floppy drives, unlike every other optional device.
> 
> I like the idea of splitting the drives from the controller. In fact, I
> think we could even try to split them into a separate hw/fdd.c
> 
> > Unfortunately, eliding the qbus means I can't make the floppy disk a
> > qdev (sub-class of TYPE_DEVICE), because qdevs can only connect to a
> > qbus.  Anthony tells me that restriction is gone in his latest QOM
> > series.
> > 
> > Since it's not a qdev, -device fdd does not work.  Pity, because it
> > defeats the stated purpose of making floppy disk drives work like
> > other existing optional devices.
> 
> As long as this is true, committing a patch like this doesn't help a
> lot, so I hope Anthony's patches will go in before this is ready.
> 
> > Note: I *break* -global isa-fdc.driveA=...  The properties are simply
> > gone.  Fixable if we need backwards compatibility there.
> 
> We might need it, I seem to remember that libvirt uses it.

Yes, since we had no other way to configure floppys, we used the -global
options. I welcome a move to bring floppys into line with other disks,
but would like us to have a little bit of overlap where -global still
works, before finally being removed in a later release.

Regards,
Daniel
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