Red Hat Bugzilla – Bug 76106
More PCI devices returned than exist, IRQ conflicts
Last modified: 2008-08-01 12:22:52 EDT
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User-Agent: Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.0; T312461)
Description of problem:
lspci returns 3 x 3com 3c900 NIC. kernel returns "kernel: eth0: Interrupt
posted but not delivered -- IRQ blocked by another device? IRQ is 15 for eth0,
same as CDROM. If CDROM is disabled, eth0 becomes disabled.
Version-Release number of selected component (if applicable):
Steps to Reproduce:
1. Install RH7.2, or 7.3 on an HP LH4, with any PCI adapters
3. Watch non-existent PCI devices get detected by Kudzu. Watch the modules fail
to load into the kernel, as they don't exist.
Actual Results: Networking performance grinds to a crawl. Errors re-occur
every 5 seconds. Logs swell up hugely. Any additional PCI devices, such as SCSI
adapters with TBU's attached will fail to load their modules.
Expected Results: System worked great with 6.2, and 7.0.
I am sure it's related to the HP LH4 hardware, and possibly the HP smart IRQ
router. Here's a kernel patch -
pci_enable_device.patch that seems to imply this multiple device issue is
specific to this model. An HP tech document suggests turning off the smart IRQ
router, in an unrelated document for Windows 2000, when accessing IRQ 9. If I
do "ifconfig eth1 down" (shutting down the 2nd NIC, eth0 also drops off the
if this is an UP system, could you try the SMP kernel?
if this is an SMP system, could you try passing "noapic" on the kernel command line?
(and that patch looks really really evil btw)
I have tried both SMP and UP kernels, in both 7.2, and am currently at 2.4.18-
10 on 7.3. I don't think I've tried passing apic to the kernel. I will do so.
I have just tested passing noapic on the command line to the kernel, and it
made no difference at all. I have also changed HP IRQ routing from smart to
fixed, in the BIOS, in case it was a related issue, and that has not made any
Thanks for the bug report. However, Red Hat no longer maintains this version of
the product. Please upgrade to the latest version and open a new bug if the problem
The Fedora Legacy project (http://fedoralegacy.org/) maintains some older releases,
and if you believe this bug is interesting to them, please report the problem in
the bug tracker at: http://bugzilla.fedora.us/