Previously, we cached _PRT (PCI routing table, ACPI 5.0 sec 6.2.12)
contents and associated each _PRT entry with a PCI bus number. The bus
number association means dependencies on PCI device enumeration and bus
number assignment, as well as on the PCI/ACPI binding process.
After 4f535093cf ("PCI: Put pci_dev in device tree as early as possible"),
these dependencies caused the IRQ issues reported by Peter:
pci 0000:00:1e.0: PCI bridge to [bus 09] (subtractive decode)
pci 0000:00:1e.0: can't derive routing for PCI INT A
snd_ctxfi 0000:09:02.0: PCI INT A: no GSI - using ISA IRQ 5
irq 18: nobody cared (try booting with the "irqpoll" option)
This patch removes _PRT caching. Instead, we evaluate _PRT as needed
in the pci_enable_device() path. This also removes the dependency on
PCI bus numbers: we can simply look at the _PRT associated with each
bridge as we walk upstream toward the root.
[bhelgaas: changelog]
Reference: https://bugzilla.kernel.org/show_bug.cgi?id=53561
Reported-and-tested-by: Peter Hurley <peter@hurleysoftware.com>
Suggested-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
181380b702