On Tue, Sep 12, 2006 at 06:00:17PM +0200, Segher Boessenkool wrote: > >Sometimes when Xen is booted and we let Linux init the MPIC for > >"the second time" Xen could end up in a loop where the CPU is > >constantly being interrupted by the MPIC. > > > >Because of console buffering, the last message you see is some > >message from early kernel boot. > >Anyway.. we detect this now and you see a panic. > > There seems to be a problem with the U3/U4 MPIC, where edge- > triggered interrupts are delivered to more than one CPU. Every > CPU other than the one that ACKed it first, will get the spurious > vector (so functionally, the impact of this bug isn't that bad; > performance-wise it might be different). > > The UART IRQ [on JS2x and Maple] is an edge IRQ; if you produce > console output for every spurious interrupt, you'll get a nice > little storm. Is that what's happening? > > >Yes, I believe, it has something to do with temperature. > > Interesting observation, never thought of investigating that -- > it's in line with my suspicion that something in the MPIC is > metastable though.
I don't know if this is realted or something else but I just got: --- *** 0000 : Setup Done [boot]0015 Setup Done Built 1 zonelists. Total pages: 49152 Kernel command line: root=/dev/hda3 ro sysrq=1 Sharing PIC with Xen -> maple_init_IRQ <6>mpic: Setting up MPIC "U3-MPIC" version 1.2 at f8040000, max 4 CPUs mpic: ISU size: 124, shift: 7, mask: 7f mpic: Initializing for 124 sources mpic: Setting up HT PICs workarounds for U3/U4 mpic: - HT:01.0 [0xb8] vendor 1022 device 7450 has 4 irqs mpic: - HT:02.0 [0xb8] vendor 1022 device 7450 has 4 irqs mpic: - HT:03.0 [0xf0] vendor 1022 device 7460 has 24 irqs (XEN) (XEN) **************************************** (XEN) Panic on CPU 0: (XEN) Too many (100) spurrious interrupts in a row (XEN) Known problem, please halt and let machine idle/cool then reboot (XEN) **************************************** (XEN) (XEN) Reboot in five seconds... --- on my JS20, rebooting cleared the error. Yours Tony linux.conf.au http://linux.conf.au/ || http://lca2007.linux.org.au/ Jan 15-20 2007 The Australian Linux Technical Conference! _______________________________________________ Xen-ppc-devel mailing list Xen-ppc-devel@lists.xensource.com http://lists.xensource.com/xen-ppc-devel
