PCI IRQ routing change broke PCMCIA/prism54 driver
Bjorn Helgaas
bjorn.helgaas at hp.com
Tue Aug 17 13:05:25 EDT 2004
On Saturday 14 August 2004 3:31 pm, Russell King wrote:
> However, with Cardbus, the socket is multi-purpose (it can contain
> a PCMCIA card or Cardbus card) and the meaning of the various signals
> is dependent on the type of card inserted. Therefore, only the
> Cardbus bridge itself knows the purpose of the signals from the
> socket.
>
> When in Cardbus mode, there is only one interrupt line for child
> devices, and this will be forwarded upstream from the bridge using
> the Cardbus bridge IRQ itself. Therefore, all child devices of a
> Cardbus bridge will always have the same PCI IRQ as the Cardbus
> bridge to which it is connected.
Thanks for the explanation. That helps the stuff in acpi_pci_irq_derive()
make sense. Are you comfortable with the code there? It feels to me
like something that should be in a per-bridge callback, but maybe that's
not necessary.
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