On Sun, Jun 10, 2012 at 02:33:03PM +0200, Jan Kiszka wrote: > On 2012-06-10 14:16, Michael S. Tsirkin wrote: > > On Sun, Jun 10, 2012 at 02:09:20PM +0200, Jan Kiszka wrote: > >> On 2012-06-10 13:39, Michael S. Tsirkin wrote: > >>> It's OK to use recursion but when done through a callback > >>> like this it's unreadable. > >> > >> Isn't the alternative poking into foreign bridge device states for their > >> secondary buses? > > > > pci_set_bus_intx_routing does this already. > > True. OK, I can do the recursion in pci_bus_fire_intx_routing_notifier > directly instead of pushing this into the bridge. > > > > >>> Also, you need to setup you cache after intx cache has been > >>> initialized, and you provide no clean way to do that. > >> > >> Once a PCI device is registered, the INTx route can be queried. So the > >> device user will call pci_device_route_intx_to_irq once (e.g. in the > >> device init function which is invoked afterward) to fill its cache and > >> receive a notification if an update is needed. I do not see why, and > >> specifically how you could query the route earlier or register a callback. > > > > Before pci_bus_irqs is called. > > Why is another question. > > > >>> > >>> One way to fix all this is call the notifier for devices, if set, from > >>> pci_set_bus_intx_routing. > >>> Then assume that intx to irq translations can be cached > >>> even though they aren't now. So you will need to invoke > >>> pci_set_bus_intx_routing on intx to irq mapping changes, > >>> and that fires the notifier for free. > >> > >> pci_set_bus_intx_routing is really only for the initial setup of the > >> static INTx pin routes. And this happens on > >> pci_bus_irqs/pci_register_bus, ie. triggered by the host bridge. By that > >> time, there can't be any notifier listeners - as there are no devices yet. > >> > >> Jan > >> > > > > What I am saying is we'll cache the final IRQ at some point. > > Pretend it's already that way so callers are ready for this. > > This wouldn't change the picture very much: Before the host bridge is > fully initialized, there is no valid route available. But before that, > there is also no device attached to it. So the invocation pattern > wouldn't change. > > What would change is the semantic of the interface to the host bridge. > So what about this: provide a public pci_root_bus_intx_routing_updated > which so far just calls the internal-use-only > pci_bus_fire_intx_routing_notifier? > > Jan >
I think a better name is pci_bus_update_intx_irq_cache or something like that. And I really think it's better to recalculate the intx routing there as well, so that if some bus implements a dynamic route_intx it just needs to call this after update. -- MST