On Wed, 7 Oct 2009, Russell King wrote: > On Wed, Oct 07, 2009 at 12:07:56PM +0200, Uwe Kleine-König wrote: > When it comes to RT and its thread-based interrupt model, the assumptions > which these handlers were designed around are no longer true. What is > now required is a different handling philosophy - rather than leaving > the interrupt-time decision about what to do with a signalled interrupt > to the flow handler, it should be immediately ack'ed and disabled, and > the interrupt thread scheduled. That's what the code does at least for the level handler. When the thread has run then the irq line is reenabled. > It is then up to the interrupt thread to determine how to handle the > interrupt - if it's really a level interrupt, then the interrupt thread > has to call the handlers before re-enabling the input. If it's edge > based, the input has to be re-enabled before running the handlers (so > that new edges received during the running of those handlers are > recognised.) That's exaclty how the RT code works :) > So, the technical aspects of handling of interrupts between the RT and > non-RT cases are quite different, and I feel that we shouldn't be > re-using the same flow handlers between the two cases. Why not. It works perfectly fine except for the case where a level type interrupt uses the edge handler :) Thanks, tglx
