On Fri, 2003-06-06 at 20:29, Kent Borg wrote: > > I am confused by something in ppc_irq_dispatch_handler(). It looks to > me that the interrupt is ack-ed before the handler is called. Maybe I > am misunderstanding, but doesn't the ack only reset the interrupt > controller? If so, the interrupting hardware could still be > presenting a level-triggered interrupt. Wouldn't it make more sense > to let the interrupt routine get service the hardware first, then > reset the interrupt controller? >
I don't know what code you are looking at but generally you want to first ack to avoid the race condition that would otherwise be present if you first run your interrupt routine then ack. How would you know that it was in fact not a new interrupt condition that you have not taken care of you just removed. ps. and never ever use edge triggered interrupts -- Kenneth Johansson Ericsson AB Tel: +46 8 719 70 20 Tellusborgsv?gen 90 Fax: +46 8 719 29 45 126 25 Stockholm ken at switchboard.ericsson.se ** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/
