Gleb Natapov <g...@redhat.com> writes:
> On Mon, Oct 25, 2010 at 06:22:12PM +0200, Markus Armbruster wrote:
>> Gleb Natapov <g...@redhat.com> writes:
>>
>> > On Mon, Oct 25, 2010 at 04:29:35PM +0200, Markus Armbruster wrote:
>> >> Gleb Natapov <g...@redhat.com> writes:
>> >>
>> >> > Without this patch both buses on PIIX3_IDE device have the same unit id.
>> >>
>> >> Are you sure that's wrong?
>> >>
>> > So how do I know which bus is it on PIIX3_IDE?
>> [...]
>>
>> Let me try to explain the IDE pointer thicket.
>>
>> piix3-ide provides two IDE buses. pci_piix_ide_initfn() stores them in
>> PCIIDEState member IDEBus bus[2]. Technically redundant, because qdev
>> stores child buses in dev.qdev.child_bus.
>>
>> IDEBus points back: qbus.parent.
>>
>> Up to two IDE devices can sit on each IDE bus. The first one uses
>> IDEBus members master and ifs[0], the second one uses slave and ifs[1].
>>
>> ifs[i].bus points back to the IDE bus.
>>
>> {master,slave}.qdev.parent_bus point back to the IDE bus.
>>
>> Say you got an IDEDevice and want to know which to which of the two
>> buses it's connected. Let's call it d.
>>
>> d->qdev.parent_bus is the BusState.
>>
>> Upcast to IDEBus: b = DO_UPCAST(IDEBus, qbus, d->qdev.parent_bus).
>>
>> b->qbus.parent is the IDE controller.
>>
>> Upcast to PCIIDEState: c = DO_UPCAST(PCIIDEState, dev, n->qbus.parent);
>>
>> If c->bus[0] == b, it's on the first bus.
>>
>> Else it must be on the second bus, i.e. c->bus[1] == b.
>>
>> Hope I didn't screw this up too badly.
> Will check tomorrow if this works, but why not have simple property on
> IDEBus that says which one is it?
Because nobody has needed it so far?
Does the bus care whether it's first or second?
> BTW what -device magic should I use to
> create secondary disk on second IDE bus?
Try -device ide-drive,bus=ide.1,unit=1,drive=...
