irq_flags bit values (can be combined, none is fine too)
IRQF_DISABLED
"Quick" interrupt handler. Run with all interrupts disabled on the current cpu (instead of just the current line). For latency reasons, should only be used when needed!
IRQF_SHARED
Run with interrupts disabled only on the current irq line and on the local cpu. The interrupt channel can be shared by several devices. Requires a hardware status register telling whether an IRQ was raised or not.