[haiku-bugs] Re: [Haiku] #9180: PANIC: unable to find irq routing for PCI 1:0:1
- From: "mmlr" <trac@xxxxxxxxxxxx>
- Date: Tue, 20 Nov 2012 15:11:50 -0000
#9180: PANIC: unable to find irq routing for PCI 1:0:1
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Reporter: Joshua | Owner: mmlr
Type: bug | Status: in-progress
Priority: normal | Milestone: R1
Component: System/Kernel | Version: R1/Development
Resolution: | Keywords: pci irq routing
Blocked By: | Blocking: 7665
Has a Patch: 0 | Platform: x86
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Changes (by mmlr):
* owner: axeld => mmlr
* status: new => in-progress
Comment:
One thing is for certain: The error should actually propagate upwards and
cause the IO-APIC not to be used. I'm going to fix this later on, though
it will probably cause a regression for you until the root cause is fixed.
I've noticed that both of the machines, the one here and the one in #9165
are of the Pentium 4 era. These are still relatively "early" in ACPI terms
and may not really do things like it is done for current hardware. At
least having the PCI Express bus separately is not so common on current
implementations AFAICT.
It is theoretically possible to map the separate PCIe roots to PCI busses,
but it requires the use of the _BBN field and comparing it to the BIOS set
bus number on the PCI host bridge. This is at least inconvenient for
Haiku, as the PCI module already sets up the busses and by that overwrites
the BIOS configured bus numbers before the interrupt routing is
determined. So to implement this mapping one would have to store these
original values somehow in the PCI module and expose a way to get at them.
In current hardware implementations the PCIe host bridges are usually
enumerated as PCI devices under the normal PCI root (this is the case here
as well from a PCI point of view) and then the ACPI tables simply follow
that and put the PCIe root as a device node on the PCI parent. This way a
simple 1:1 mapping while enumerating both busses can be done. This is what
is currently implemented in Haiku.
A possibly better approach to this whole mess and back and forth with PCI
would be to make the PCI module responsible for the whole interrupt
routing mechanism. This would make sense as what is currently done is
really just PCI interrupt routing, not any kind of other interrupt routing
(as there aren't any other interrupt sources that use this kind of routing
on x86). So putting it in the PCI module would make sense. It would reduce
the knowledge and redundancy the kernel has about PCI for this task at
least, which would be much cleaner.
--
Ticket URL: <http://dev.haiku-os.org/ticket/9180#comment:4>
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