[mythtv-users] dmesg: Misrouted IRQ fixup and polling support enabled

[Abhi]

I see the following in the dmesg of my linux/mythtv box (2.6.16-1.2108_FC4)

> dmesg
[...]
Kernel command line: ro root=LABEL=/ rhgb vga=791 noapic pci=routeirq 
irqpoll quiet
Misrouted IRQ fixup and polling support enabled
This may significantly impact system performance
[...]

Wondering what this means!
How can I make sure that IRQs are not misrouted...

> more /proc/interrupts
           CPU0
  0:    3556171          XT-PIC  timer
  2:          0          XT-PIC  cascade
  3:          0          XT-PIC  ohci_hcd:usb2
  5:         30          XT-PIC  ohci_hcd:usb4
  6:          3          XT-PIC  ehci_hcd:usb1
  7:      45225          XT-PIC  ohci_hcd:usb3
  8:          1          XT-PIC  rtc
  9:          1          XT-PIC  acpi
 10:    5753556          XT-PIC  ivtv0
 11:          1          XT-PIC  yenta
 14:     200885          XT-PIC  ide0
 15:       4647          XT-PIC  SiS SI7012, eth0
NMI:          0
LOC:    3556309
ERR:          1
MIS:          0

Without the noapic option, the dmesg gets flooded with the following:

APIC error on CPU0: 40(40)
APIC error on CPU0: 40(40)
APIC error on CPU0: 40(40)
APIC error on CPU0: 40(40)
APIC error on CPU0: 40(40)
APIC error on CPU0: 40(40)
APIC error on CPU0: 40(40)
ACPI: Power Button (FF) [PWRF]
ACPI: Power Button (CM) [PWRB]
ibm_acpi: ec object not found

Also, I have started seeing the following in the dmesg (with or without 
noapic):
hda: cdrom_pc_intr: The drive appears confused (ireason = 0x01)

Does this indicate a bad CDROM hardware, or is it some IRQ problem?



thanks
- Abhi