Re: [PATCH 0/3] v4.4: Revert "PCI: Implement pcibios_alloc_irq() and

[Joerg Roedel]

On Mon, Apr 18, 2016 at 09:43:36AM -0500, Bjorn Helgaas wrote:
> That might work, but the problem seems to be that we aren't enabling
> IRQs correctly, so I'd rather have a fix that explicitly addresses
> IRQs than one that relies on some non-obvious connection between
> enabling BARs and IRQs.

Yeah, either we or the BIOS does something wrong. The bugzilla entry
states that it works with pci=routeirq. The dmesg from kernel 4.3 shows
that per default ACPI routing is used for IRQs.

The difference this makes in the code is the pcibios_enable_irq function
pointer. For ACPI it points to acpi_pci_irq_enable and in the
pci=routeirq case to pirq_enable_irq.

So the problem appears when acpi_pci_irq_enable is used with device
resources disabled. This might very well also be a bios issue that we
have to work around, no?



	Joerg