Hello.

Anton Vorontsov wrote:

quoted

quoted

But some hardware (namely ULi M5228 in the ULi M1575 "Super South Brige")
behaves in a strange way: it asserts interrupts as edge sensitive. And
because preemptable IRQ handler disables PIC's interrupt, PIC will likely
miss it.
  
      

  Unmasking an IRQ should re-enable an edge detector in a PIC (or that  
detector should even be independent from mask).
    

Should? Hm.. well, I can easily check it. Will just program the MPIC IRQ
to edge sensitive, and see if it fixes the problem (not sure if I already
tried this, I think I did try).
  

   That will not help if edge detector is not active for masked out IRQs 
(that's how i8259 behaves, IIRC) *and* you're getting the short IRQ 
"pulses" but should help if IRQ is generated normally -- though in this 
case the level trigger mode (with the same polarity) should work as well...

MBR, Sergei