Re: [PATCH v2 -rt] ide: workaround buggy hardware issues with preemptablehardirqs

[Sergei Shtylyov]

Hello.

Anton Vorontsov wrote:
> > > 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


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