Sandy Bridge PCI Card Drivers Fail with "Disabling IRQ"

[aklhfex]

I wasn't aware of problems with PCI cards on Sandy Bridge (until I bought an Asus P8Z68-V LX) even though there seem to be quite a few reports out there. No fix appears to have been developed (I have tried 3.1-rc10). The only thing to help is booting with irqpoll kernel parameter which seems to reduce the number of occurrences.

Most reports appear to be about Asus boards, but I did find one about an Intel DH67BL:
http://lists.centos.org/pipermail/ce...ry/104590.html

Some other reports, there are some links in them to bugzilla.kernel.org but of course they are impossible to read at the moment.
https://lkml.org/lkml/2011/6/30/197
https://lkml.org/lkml/2011/10/14/146
https://bugzilla.redhat.com/show_bug.cgi?id=713351
https://bugs.launchpad.net/ubuntu/+s...ux/+bug/877588
http://ubuntuforums.org/showthread.php?t=1676491

[aklhfex]

Seems to be a more general regression introduced by IRQ code re-factoring in recent kernels:
https://bugs.launchpad.net/linux/+bug/855199

One fix already committed for 3.2:
http://git.kernel.org/?p=linux/kerne...ea383621027bf2

Is there more needed?:
https://lkml.org/lkml/2011/11/19/189

Thanks Edward!!!

[aklhfex]

First fix now in 3.1.3 too and second accepted for 3.2:
http://git.kernel.org/?p=linux/kerne...88d5818f57f62a

But... although they plus irqpoll reduces the frequency it is still not completely fixed for me.

[aklhfex]

Looks like suspicion is falling on the ASM1083 PCI Express-to-PCI bridge chip:
https://lkml.org/lkml/2011/12/9/129

Hopefully this interest means there will be a complete solution.

[AlbertP]

The Sandy Bridge chipsets don't have PCI support anymore, that's why board vendors use a bridge chip. The ASM1083 is quite a common one but ASMedia doesn't seem to be very Linux-friendly. Usually PCI or PCI Express bridges just work, without needing a driver, but this chip is buggy and probably only tested with Windows.

I hope motherboard vendors will start to use JMicron chips instead. JMicron supports Linux somehow, as they list the minimal kernel version required for a device to work on their website.

[aklhfex]

The Intel DH67BL mentioned above uses an ITE IT8892E:
http://www.lostcircuits.com/mambo//i...1&limitstart=4
http://www.overclockersclub.com/vima...5_2500k/54.jpg

Not that Intel claims Linux support:
http://www.intel.com/support/motherb.../cs-008326.htm

Gigabyte also appear to use ITE, with the GA-H67A-USB3-B3 manual saying it has an ITE IT8892.

It would be interesting to hear from anyone that does have PCI working.

[AlbertP]

That ITE chip is not the PCI bridge. It's the Super I/O chip which means it handles PS/2, parallel, serial, and floppy, and often also hardware monitoring, along with a lot of BIOS stuff. It's not related to PCI at all. You can't even see the Super I/O chip of a motherboard in the lspci output.

The first link clearly mentions it as a Super I/O chip.

[AlbertP]

Here's a picture of the ASMedia chip:
http://www.modlabs.net/uploads/galle...ia-asm1083.jpg

[aklhfex]

Every link I can find says the ITE IT8892E is the PCI bridge - although I can't find an actual specification.

[AlbertP]

(please remove this post)