On Wed, Feb 01, 2012 at 05:34:01PM -0800, Eric W. Biederman wrote: > > Talking to folks here and trying to read the code it seems like the PIT > > stuff is delayed until after the IOAPIC is configured using Fast TSC > > calibration as a mechanism to work around the PIT?? > > > > I attached the output of the Pentium4 when kdumping. Not sure what to > > really look for to verify the PIC is being skipped. Perhaps you know? > > The important part is the kexec on panic works without shutting down > the ioapic. There should be no corner case issues it should either > work it should fail. > > The problem used to be that we always would initialize the PIT interrupt > in the 8259 interrupt controller before we would initialize the ioapics > and that would kill the boot. > > If I have read your testing correctly you are apparently booting in the > kexec on panic case. That seems to be successful to me. So we should > be able to just remove the ioapic shutdown code from > machine_crash_shutdown as it is no longer needed. > > Thank you for being careful and testing on a number of different > platforms. No problem. I was actually trying to find machines that did not have ioapics to make sure they still worked (it's hard!). So if I test on a couple more machines (hopefully one without an ioapic), can I get your ack? Or is there something else you would like me to do to verify things are working correctly? I will also need your help writing the changelog such that people understand why removing that line is safe now. > > The only case I can think that won't work without ioapic disables > is using a crash kernel that doesn't emable the ioapics. Ok. I can see that. Would you agree that scenario is not a very sane case? :-) Does not using the ioapic really save you anything? Otherwise the alternative is to use my original patch. Thanks for the help. Cheers, Don > > Eric
