[Bug 53835] Re: ACPI startup causes unhandled IRQ.

[Patrick Dixon]

I have what I think is a similar problem with a A8V-MX motherboard.

dmesg output is as follows:

[   57.411434] [drm] Initialized drm 1.1.0 20060810
[   57.427919] ACPI: PCI Interrupt 0000:01:00.0[A] -> GSI 16 (level, low) -> IRQ 20
[   57.428521] [drm] Initialized via 2.10.0 20060529 on minor 0
[   57.429010] [drm] Initialized via 2.10.0 20060529 on minor 1
[   57.643029] agpgart: Found an AGP 3.0 compliant device at 0000:00:00.0.
[   57.643147] agpgart: Putting AGP V3 device at 0000:00:00.0 into 8x mode
[   57.643300] agpgart: Putting AGP V3 device at 0000:01:00.0 into 8x mode
[   58.036175] eth0: no IPv6 routers present
[   60.033467] irq 20: nobody cared (try booting with the "irqpoll" option)
[   60.033476]  [<c0151534>] __report_bad_irq+0x24/0x80
[   60.033489]  [<c01517e0>] note_interrupt+0x250/0x290
[   60.033501]  [<c0150aa5>] handle_IRQ_event+0x25/0x50
[   60.033510]  [<c015210d>] handle_fasteoi_irq+0xbd/0xd0
[   60.033518]  [<c0105960>] do_IRQ+0x40/0x80
[   60.033528]  [<c0104103>] common_interrupt+0x23/0x30
[   60.033532]  [<c0101e00>] default_idle+0x0/0x40
[   60.033545]  [<c0101e2f>] default_idle+0x2f/0x40
[   60.033551]  [<c01013f9>] cpu_idle+0x49/0xc0
[   60.033557]  [<c03cb7c6>] start_kernel+0x336/0x3b0
[   60.033562]  [<c03cb230>] unknown_bootoption+0x0/0x260
[   60.033577]  =======================
[   60.033579] handlers:
[   60.033580] [<dca311c0>] (cx8800_irq+0x0/0x230 [cx8800])
[   60.033587] [<dca49160>] (cx8802_irq+0x0/0x2d0 [cx8802])
[   60.033594] [<ddcba480>] (via_driver_irq_handler+0x0/0x1d0 [via])
[   60.033600] Disabling IRQ #20

The problem affects a PCI card installed into slot 1 since it shares
this pci interrupt.  Once the IRQ is disabled, the card's interrupts go
unhandled.  I've tried booting with irqpoll, but that doesn't seem to
solve the problem.

Have tried 2.6.10, 2.6.11 and 2.6.20 kernels with the same result.  The
IRQ number is different each time, but is always the one allocated to
this device.

:~$ cat /proc/interrupts
           CPU0
  0:     703959   IO-APIC-edge      timer
  1:        542   IO-APIC-edge      i8042
  6:          5   IO-APIC-edge      floppy
  7:          0   IO-APIC-edge      parport0
  8:          3   IO-APIC-edge      rtc
  9:          1   IO-APIC-fasteoi   acpi
 12:       9279   IO-APIC-edge      i8042
 14:     519410   IO-APIC-edge      ide0
 15:          0   IO-APIC-edge      libata
 16:          0   IO-APIC-fasteoi   uhci_hcd:usb3
 17:          0   IO-APIC-fasteoi   uhci_hcd:usb1
 18:       1334   IO-APIC-fasteoi   uhci_hcd:usb2, ehci_hcd:usb5, VIA8237
 19:       7797   IO-APIC-fasteoi   uhci_hcd:usb4, eth0
 20:     300000   IO-APIC-fasteoi   cx88[0], cx88[0], via at pci:0000:01:00.0
221:          0   PCI-MSI-edge      libata
NMI:          0
LOC:     703964
ERR:          0
MIS:          0

-- 
ACPI startup causes unhandled IRQ.
https://launchpad.net/bugs/53835