Why ack interrupt before calling handler?

Kenneth Johansson kenneth.johansson at etx.ericsson.se
Wed Jun 11 22:58:32 EST 2003

On Wed, 2003-06-11 at 14:39, Kent Borg wrote:
> On Wed, Jun 11, 2003 at 12:33:42PM +0200, Kenneth Johansson wrote:

> Finally the interrupt end gets called, which acks and enables the
> interrupt.  This ack actually does something for me.

Hopefully this ack only happens if the interrupt is level triggered
otherwise you have a problem.

> I am thinking that the general purpose PPC code does the early
> ack for edge-triggered circumstances.  For latched level-triggered
> cases there is no harm in the extra early ack.

Thats right.

Kenneth Johansson
Ericsson AB                       Tel: +46 8 719 70 20
Tellusborgsvägen  90              Fax: +46 8 719 29 45
126 25 Stockholm                  ken at switchboard.ericsson.se

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