Re: Assertion duration of edge interrupts can decrease spurious interrupts ..?

[Ralf Baechle <ralf@linux-mips.org>]

On Tue, Nov 18, 2003 at 06:57:41AM -0000, ashish  anand wrote:

> 1.If i have a compulsion to use egde triggering peripheral on MIPS CP0,
> would it be useful if i can increase the assertion duration of edge
> interupts (this I can do) ..I mean to say probablity of loosing edge
> interrupts will decrasse.

That would help but still not be a safe mechanism.  Not only the processor
may be missing the edge - Linux may also disable interrupts for quite a
long time.  You'd have to use a hard realtime variant of Linux or you will
loose interrupts ...

> 2.does CP0 interrupt logic samples interrupts after each instruction or
> at some multiplication(..or division.?) of system clock.

This is a very processor specific detail.  R4000 for example will sample
interrupts on pipe stage 3; something along that lines is probably done
in most in-order processors.

  Ralf