3c509 forces itself into an IRQ conflict

[Kimmo_S]

I'm having an IRQ conflict.

When I boot Debian, vanilla kernel 2.4.22, everything is fine.
eth0 3c509 is IRQ 9, IO 0x210
eth1 3c509 is IRQ 5, IO 0x300
hisax HFC-PCI ISDN is IRQ 12
Adaptec AHA152x is IRQ11, IO 0x340
All cards work flawlessly and as expected. modules.conf has line "options 3c509 irq=9"

When I boot Gentoo on the same machine, eth0 3c509 steals IRQ 12, no matter what I do. Compiling 3c509 in and giving a kernel command-line as described in linux/Documentation/networking/3c509.txt didn't help. All logs have that it takes IRQ 12 (or is found at IRQ 12). Giving irq=9 as a parameter doesn't help if I manually run modprobe. I've also tried including "3c509 irq=9" into Gentoo's /etc/modules.autoload.d/kernel-2.6 to no avail. It just doesn't care that I'm asking it to try IRQ 9. Booting back to Debian, eth0 is found at irq=9, and everything is fine again.

Debian doesn't have ISAPnP package installed, and when I installed it on Gentoo, pnpdump found nothing. So I guess that I have set both 3c509 cards to use non-PnP initalisation. Gentoo has 2.6.4 kernel. The machine is a Pentium 133MHz with Intel HX chipset and PIIX3 IDE controller.

I had modprobe segfault a few times when I had 3c509 in /etc/modules.autoload.d/kernel-2.6 but now it just says "SIOCSIFFLAGS: Device or resource busy" if I try to do something. 3c509 doesn't appear in /proc/interrupts, except when I remove hisax from /etc/modules.autoload.d/kernel-2.6, but then it appears as IRQ 12, which is the whole problem.

[Kimmo_S]

In Debian, the cards are found at IRQ 12 and 5 on boot, according to logs, but ifconfig says they are IRQ 9 and 5, and they work as expected. I can remove and insert the module as many times as I want when the corresponding eth interface is down. Every time it finds cards at IRQ 12 and 5, and every time "ifconfig up eth0 ; ifconfig" shows the card at IRQ 9, and the other (eth1) at IRQ 5. I can switch the cards (interfaces) by "modprobe 3c509 irq=5,9", and I can set up an IRQ conflict by "modprobe 3c509 irq=12,5", and eth0 then refuses to come up, but after "rmmod 3c509" I can again "modprobe 3c509", the cards are found at 12 and 5, and ifconfig again says IRQ 9 and 5, and everything works.

I found out that /etc/modules.conf made the first card IRQ 9, and with an "option" line there removed, I had to specify irq=9 to modprobe, or the card went to IRQ 12, and "ifconfig eth0 up" resulted in "SIOCSIFFLAGS: Device or resource busy".

With Gentoo, once someone or something modprobes 3c509, it is there and can't be removed. And it never obeys any irq parameters. By removing hisax I was able to do "ifconfig eth0 up" (with no error messages), but ifconfig said eth0 is IRQ 12, /proc/interrupts showed 0 interrupts for it, and no traffic could go in or out.

I Googled for kernel changelogs. There was a mention of 3c509, like "3c509: FIXED" in some rc of 2.6.5, so I installed the newest sys-apps/development-sources, which is 2.6.6-rc1, but nothing changed.