@@ -607,7 +607,14 @@ individually. Instead, a set of devices sharing a power resource can be put
into a low-power state together at the same time by turning off the shared
power resource. Of course, they also need to be put into the full-power state
together, by turning the shared power resource on. A set of devices with this
-property is often referred to as a power domain.
+property is often referred to as a power domain. A power domain may also be
+nested inside another power domain.
+Devices and PM domains may be defined as IRQ-safe, if they can be powered
+on/off even when the IRQs are disabled. An IRQ-safe device in a domain will
+disallow power management on the domain, unless the domain is also defined as
+IRQ-safe. The restriction this framework imposes on the parent domain of an
+IRQ-safe domain is that it must also be defined as IRQ-safe.
Support for power domains is provided through the pm_domain field of struct
device. This field is a pointer to an object of type struct dev_pm_domain,