reactos/doc/irql.txt

   1 This document describes the state of a uniprocessor PC at each of the IRQ
   2 levels supported by the ReactOS kernel
   3
   4 PASSIVE_LEVEL:    IF bit clear in the processor flags
   5                   All irqs umasked at the PIC
   6
   7 APC_LEVEL: Unknown
   8 WAKE_LEVEL: Unknown
   9
  10 DISPATCH_LEVEL:   IF bit clear in the processor flags
  11                   All irqs umasked at the PIC
  12                   Thread dispatching disabled
  13
  14 DIRQL (Device specific IRQ level):
  15           IF bit clear in the processor flags
  16           Device's irq and all lower priority irqs masked at the PIC
  17           Thread dispatching disabled
  18
  19 HIGH_LEVEL:       IF bit set in the processor flags
  20                   All irqs masked at the PIC
  21                   Thread dispatching disabled