8.1-RC2 - PCI fatal error or MCE triggered by USB/ehci on Sun X4100M2?

[Markus Gebert]

On 10.07.2010, at 01:53, Markus Gebert wrote:

>> I'm curious if disabling USB legacy support in the BIOS causes it to still die 
>> even with ehci not loaded.  If so, then the SMI# for the ehci controller must 
>> somehow prevent the issue, perhaps by triggering frequently enough to slow the 
>> rate of I/O requests down?
> 
> 
> I disabled usb legacy support in the BIOS and booted a kernel with usb+ohci+ukbd+ums but without ehci. Unfortunately, I cannot reproduce the MCE.


Well, the situation has changed. Machine died over the weekend running our test load with above kernel configuration. It seems that not having ehci in the kernel at boot just makes the MCE much more unlikely to occur, but it occurs. With ehci, I can panic the machine within a minute, without ehci it seems to take at least hours. Still, I don't get why not having the ehci driver in the kernel should have any effect, especially because nothing is attached to it.

Panic message:

----
MCA: Bank 4, Status 0xb400004000030c2b
MCA: Global Cap 0x0000000000000105, Status 0x0000000000000007
MCA: Vendor "AuthenticAMD", ID 0x40f13, APIC ID 2
MCA: CPU 2 UNCOR BUSLG Observer WR I/O
MCA: Address 0xfd00000000
panic: blockable sleep lock (sleep mutex) 128 @ /usr/src/sys/vm/uma_core.c:1992
cpuid = 2
KDB: enter: panic
[thread pid 12 tid 100039 ]
Stopped at      kdb_enter+0x3d: movq    $0,0x69ccb0(%rip)
----

Don't know, why it's not a fatal trap 28 this time despite an MCE was detected. Seen this before though, also with kernels that have ehci and with usb legacy support, so seeing a different panic this time seems not related to the way the kernel was configured. Maybe a symptom? Or may it even be useful? If yes, what should I pull out of DDB?

In the meantime, I'll try harder to reproduce the MCE on current...


Markus