Interrupts randomly stop firing

[buserror]

I'm fairly sure commit 5e6256ae is creating random problems with interrupts stopping. I've tracked cases where I have some 'pending' but they never get fired afterward. My suspicion is that the code of that commit that tries to 'optimize' wether there are IRQs or not is broken in some subtle way. In fact, it's likely when there are multiple IRqs pending at the same time.