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); > This will not work if IDEBus sits on ISA bus. Any other ideas?
> 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. -- Gleb.