Re: IRQ problems??

From: Rod Morison
Date: Mon Jan 30 2006 - 04:22:18 EST


I got the same amount of reply when I posted a similar problem ("mptable irq info wrong on Tyan S5112, need advice") a few days before you.

What I have debugged is (for the 2.4 kernel) the motherboard IRQ tables that are passed to the kernel via mpparse.c are dead wrong. In my case, I was able to hack the kernel and hunt down the correct interrupt. I'm actually surprised that there aren't more systematic IRQ debug utilities out there in the Linux world, given how many problems go unsolved across many lists.

I'm trying to build a small knowledge base on this breed of problem (bad IRQ assignments due to motherboard snafus). I've got a couple writeups in the works, but the first is about a very useful utility that dumps the mobo IRQ info (the mptable data, to be specific): http://www.morison.biz/technotes/articles/view.php/12

Rod



Quoting WSteffen:

I am working with an HP Pavilion a1210n the mother board is
an ASUS A8AE-LE, which has an ATI IXP SB440 and a Realtek
ethernet controller. The processor is an AMD Athlon 64 3500+.
The USB controllers will not function unless ACPI is enabled
in the kernel.
If ACPI is enabled in the kernel the realtek ethernet is not
usable. If I do a ping to a working device on the same net,
I can see ARP requests going out and replies coming back.
However I get "host unreachable" error messages.
When looking at the interrupts in each case it appears to me
that there is an IRQ assignment problem. (my guess is the
Realtek driver) or is there something I am doing wrong??
Below are the contents of /proc/interrupts:

With ACPI set:
CPU0
0: 135197 XT-PIC timer
1: 315 XT-PIC i8042
2: 0 XT-PIC cascade
5: 8 XT-PIC eth1
7: 0 XT-PIC parport0
9: 3 XT-PIC acpi
11: 208 XT-PIC libata, ehci_hcd:usb1, ohci_hcd:usb2,
ohci_hcd:usb3, eth0
12: 5202 XT-PIC i8042
15: 4451 XT-PIC ide1
NMI: 0
ERR: 0

CPU0
0: 37706 XT-PIC timer
1: 225 XT-PIC i8042
2: 0 XT-PIC cascade
5: 8 XT-PIC eth1
10: 6 XT-PIC eth0
11: 2 XT-PIC libata
12: 110 XT-PIC i8042
15: 4398 XT-PIC ide1
NMI: 0
ERR: 0

With ACPI not set:

If there is something I am doing wrong, please let me know!!

Thanks
Warren Steffen
wsteffen@xxxxxxxxxxx
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