Marc Wilson wrote: > Daniel B. wrote: > > Bob Proulx wrote: > > > Daniel B. wrote: > > > > Oct 18 20:29:30 dsb kernel: spurious 8259A interrupt: IRQ7. > > > Just ignore it. It basically means that you do not have anything > > > connected to the parallel port. > > That obviously can't be right--I have a working printer attached to > > the parallel port.
Hmm... I only see the messages on machines without anything connected. On machines with printers on the parallel port I never see that message. I had been assuming it had something to do with MOS circuits (as opposed to the original TTL totem pole logic) floating just enough after a power up reset that they were asserting the interrupt line in a bogus manor and assuming that having a real something on the port kept the wire deasserted. But I guess that argument could be used both ways. > It isn't right. What it means is that an interrupt was asserted, but by > the time the hardware got around to telling the CPU, it wasn't there any > more. IRQ7 is the lowest priority interrupt, and that's where the service > routine ends up. That isn't right either. IRQ7 is not the lowest priority interrupt and neither do routines just end up there. At least we are both posting what appears to be bogus information. :-) Basically the 8259A is the interrupt controller used in PCs since the first IBM XT. The IRQ7 line was asserted. The PIC generated the CPU interrupt. The CPU interupt service routine looked for something registered to service IRQ7 and found nothing registered. So it listed the interrupt as spurious and went, "nothing to see here, move along". The linux kernel mailing list archives are filled with discussion of this problem. It has the usual 'net cycle of reappearing every few months. Even so it is not (yet) in the FAQ and no definitive guides exist that I am aware of to deal with it. There appears to be a trend that people think it might be associated with various network card drivers. But that does not seem right to me. > It's harmless. At least we are agreed on that. :-) It is harmless. Ignore it. Bob
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