Well, I have a new culprit of the hour: gregkh-pci-pci-use-pci_bios-as-last-fallback There was a previous patch that messed up a few of my machines and this same driver a few months ago, which accounts for my sense of deja vu: http://www.kernel.org/pub/linux/kernel/people/akpm/patches/2.6/2.6.16-rc6/2.6.16-rc6-mm1/broken-out/gregkh-pci-pci-give-pci-config-access-initialization-a-defined-ordering.patch There was an off-list thread called "PCI device issue in 2.6.16-rc3-mm1 through 2.6.16-rc6-mm1" Anyway, here's the information from the syslog at boot in a working system (without the patch applied): PCI: PCI BIOS revision 2.10 entry at 0xfd32c, last bus=8 Setting up standard PCI resources SCSI subsystem initialized PCI: Probing PCI hardware PCI: Discovered peer bus 02 PCI: Firmware left 0000:02:05.0 e100 interrupts enabled, disabling PCI: Discovered peer bus 05 PCI->APIC IRQ transform: 0000:00:05.0[A] -> IRQ 16 PCI->APIC IRQ transform: 0000:00:0f.2[A] -> IRQ 19 PCI->APIC IRQ transform: 0000:02:01.0[A] -> IRQ 17 PCI->APIC IRQ transform: 0000:02:01.1[B] -> IRQ 18 PCI->APIC IRQ transform: 0000:02:05.0[A] -> IRQ 24 PCI->APIC IRQ transform: 0000:05:02.0[A] -> IRQ 21 PCI->APIC IRQ transform: 0000:05:02.1[B] -> IRQ 26 PCI->APIC IRQ transform: 0000:06:04.0[A] -> IRQ 22 PCI->APIC IRQ transform: 0000:06:05.0[A] -> IRQ 27 PCI->APIC IRQ transform: 0000:06:06.0[A] -> IRQ 28 PCI->APIC IRQ transform: 0000:06:07.0[A] -> IRQ 29 PCI: Bridge: 0000:05:03.0 IO window: 7000-7fff MEM window: eb000000-ec1fffff PREFETCH window: ea300000-ea3fffff And the same thing in a system where it can't find my SCSI card (with the patch applied): PCI: Using configuration type 1 Setting up standard PCI resources SCSI subsystem initialized PCI: Probing PCI hardware PCI->APIC IRQ transform: 0000:00:05.0[A] -> IRQ 16 PCI->APIC IRQ transform: 0000:00:0f.2[A] -> IRQ 19 -- Dave - : send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html