Messages in this thread | | | From | (Alan Cox) | Subject | Re: Strange interrupt behaviour | Date | Sat, 11 Jul 1998 16:06:23 +0100 (BST) |
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> I'm also seeing interrupt funnies in various later 2.1.x. > The extremely trivial interrupt routine in baycom_ser_hdx (if > you uncomment calls to the actual rx/tx functions) fails > there with 3600int/s, however if I reduce the int rate > it works.
I've now catalogued four different types of breakage still present in 2.1.10x IRQ handling
1. The latency has gone completely to shit. Its so slow handling IRQ's that I can no longer run 64Kbit synchronous on 2.1.x kernels. People with sync cards are trapped in 2.0 or blow $500 on a smart card. This we have to sort - even NT can do 64K sync cards.
2. Edge triggered PCI on old motherboards (PPro 120 sort of era) running SMP crash and burn on boot (third party report)
3. Drivers that get repeated interrupts appear to re-enter the handler uncontrollably blow the stack and crash. I suspect nested interrupt handling problems may be half the 8K stack issue, and could be tons of our other remaining bugs.
With my sync card this works
foo_interrupt(){...return...}
this crashes
foo_interrupt(){save_flags(flags);restore_flags(flags);}
4. We've lost the fast irq stuff. Thats unbelievably bad and may be part of #1.
Alan
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