Re: [Xen-devel] Xen4.2 S3 regression?

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 19.09.12 at 23:07, Ben Guthro <ben@xxxxxxxxxx> wrote:
> No hardware debugger just yet - but I've moved to another machine (Lenovo
> T400 laptop) - and am now seeing the following stack trace when I resume
> (this is using the tip of the 4.2-testing tree)

Considering that the situation is similar to the one with very early
boot problems - as long as the system either reboots on its own
(albeit I don't think you ever said it does) or has a reset button
(or other way to initiate reset without turning off power), an
alternative debugging method would be to write data into I/O
ports the values of which persist across reset, and read them out
during the following boot. I have found the 0x008x range to be a
candidate for this, as well as certain DMA controller ones. And of
course, if the CMOS RAM has its upper 128 bytes present and
(part of it) usable (i.e. otherwise unused), that would even be
an option permitting power cycling the system without losing the
information.

Jan


_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel