Subject: Re: [PATCH] FRV: do_gettimeofday() should no longer use tickadj

From: Benjamin Herrenschmidt <[email-masked]>
Date: Thu, 07 Sep 2006 09:01:32 +1000

> Under some circumstances I can work out which sources have triggered which
> interrupts (there are various off-CPU FPGAs which implement auxiliary PICs that
> do announce their sources), but the aux-PIC channels are grouped together upon
> delivery to the CPU PIC, so some of the ACK'ing has to be done at the group
> level.
> 
> > how is this not possible via genirq?
> 
> How is it possible with genirq?

Well, genirq gives you more flexibility than the current mecanism so ...

If I understand correctly, you need to do scray stuff to figure out your
toplevel irq, which shound't be a problem with either mecanisms... 

Now, if you have funky cascades, then you can always group them into a
virtual irq cascade line and have a special chained flow handler that
does all the "figuring out" off those... it's up to you. 

In general, I found genirq allowed me to do more fancy stuff, and end up
with actually less hooks and indirect function calls on the path to a
given irq than before as you can use tailored flow handlers that do just
the right thing.

Ben.