Hi fellow Xen developers,
I continue to get system hangs where the watchdog NMI in Xen
is not doing its job. I am completely blind as to what is getting jammed.
Tried multiple experiments to force the hang and in each, the watchdog has
kicked in, so I know the mechanism works 99% of the time except in my one hang.
So in the old days of PCI bus, I used to be able to generate
a HW NMI by asserting the SERR signal in the connector. With the advent
of PCIe, I believe that signal is no longer present, so I am looking for any
other way to cause a system error. I have examined the PCI
express mini-card specification looking for a signal I can use in the internal
WiFi connector, but alas, none of the signals I read about seem like they would
do what I need. I am not sure if there is anything I can short in the
PCIe signals that could have a similar effect as the SERR signal. The
platform is a Lenovo T500 laptop so the number of connectors to play with is
limited.
I also thought of causing a parity/ECC error but the GM45
chipset used in this laptop does not support ECC memory.
So I’m basically looking for any other ideas on how to
cause a fault by probing somewhere in the motherboard. This MB has a
docking station connector but I have not been able to find the pinout list so I
don’t know what is brought out there. At this point, I have no
problem cracking up the case and soldering something on to the motherboard.. I
just need to know what chips and signals to tap.
Thanks in advance.
Roger R. Cruz
