On Mon, Jun 13, 2011 at 05:51:11PM -0400, Guenter Roeck wrote: [ ... ] > > > > > > The actual interrupt causing trouble and spurious interrupts in my case is, > > > oddly enough, STATUSF_IP0. So far I have been unable to track down how that > > > is triggered; I don't see the bit being set set in C0_CAUSE anywhere. > > > > > > Are there any means to trigger an IP0 interrupt other than by writing STATUSF_IP0 > > > into the C0_CAUSE register ? > > > > > > > No. Nothing that I know of ever uses IP0 and IP1, so they should always > > be cleared. > > > Exactly what I figured, yet I still get those spurious interrupts if IP0 is enabled. > Something odd is definitely going on in my system. > > Besides the above, my hopefully final problem is that timer interrupts are only > received by CPU 0. Any idea what to look for to fix this problem ? > Found the problem. Apparently the BIOS resets CvmCtl[IPTI] to 0. This causes both the spurious interrupt on IP0 without setting C0_CAUSE, and the (perceived) lack of timer interrupts. In other words, it _is_ possible to trigger IP0 interrupts without setting STATUSF_IP0 in C0_CAUSE ... the interrupt will happen, but C0_CAUSE will not be set. Interesting learning experience... Thanks, Guenter
