Hi Jacky, On Wed, Mar 2, 2011 at 6:26 PM, Jacky Lam <lamshuyin@xxxxxxxxx> wrote: > Hi Dave, > > I have confirmed the execution has go into > desc->irq_data.chip->irq_disable(&desc->irq_data); > > However, irq_disable points to kernel/irq/chip.c:default_disable() which > do nothings. > Unlike default_enable() which called by enable_irq() will unmask the IRQ > accordingly. > > I don't understand the reason behind. Which irq chip is being used? It's really up to the individual irq chip driver to implement things in an appropriate manner. Since the IRQ_DISABLED flag is set, if the interrupt happens to fire again, your handler shouldn't be called. The generic handler masks interrupts when they occur, and if the IRQ_DISABLED flag is set then it will leave the interrupt masked (i.e. disabled). Look at the the __do_IRQ function in handle.c <http://lxr.linux.no/linux+v2.6.36.4/kernel/irq/handle.c#L446> So even though it looks like its not doing things, the interrupt is still effectively disabled. -- Dave Hylands Shuswap, BC, Canada http://www.davehylands.com _______________________________________________ Kernelnewbies mailing list Kernelnewbies@xxxxxxxxxxxxxxxxx http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
