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authorLina Iyer <lina.iyer@linaro.org>2016-10-24 14:38:47 -0700
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2016-10-24 23:48:22 +0200
commit411bf2a8db76d7ed6f710df77121e5113ee8fe64 (patch)
treea31018fadf532930745d47525d867c5c5764fe15 /Documentation/power
parentd716f4798ff8c65ace4a6ab291f9a4ff265df4ba (diff)
downloadlinux-411bf2a8db76d7ed6f710df77121e5113ee8fe64.tar.bz2
PM / doc: Update device documentation for devices in IRQ-safe PM domains
Update documentation to reflect the changes made to support IRQ safe PM domains. Suggested-by: Rafael J. Wysocki <rjw@rjwysocki.net> Signed-off-by: Lina Iyer <lina.iyer@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'Documentation/power')
-rw-r--r--Documentation/power/devices.txt14
1 files changed, 13 insertions, 1 deletions
diff --git a/Documentation/power/devices.txt b/Documentation/power/devices.txt
index 8ba6625fdd63..73ddea39a9ce 100644
--- a/Documentation/power/devices.txt
+++ b/Documentation/power/devices.txt
@@ -607,7 +607,9 @@ 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. The nested domain is referred to as the
+sub-domain of the parent domain.
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,
@@ -629,6 +631,16 @@ support for power domains into subsystem-level callbacks, for example by
modifying the platform bus type. Other platforms need not implement it or take
it into account in any way.
+Devices may be defined as IRQ-safe which indicates to the PM core that their
+runtime PM callbacks may be invoked with disabled interrupts (see
+Documentation/power/runtime_pm.txt for more information). If an IRQ-safe
+device belongs to a PM domain, the runtime PM of the domain will be
+disallowed, unless the domain itself is defined as IRQ-safe. However, it
+makes sense to define a PM domain as IRQ-safe only if all the devices in it
+are IRQ-safe. Moreover, if an IRQ-safe domain has a parent domain, the runtime
+PM of the parent is only allowed if the parent itself is IRQ-safe too with the
+additional restriction that all child domains of an IRQ-safe parent must also
+be IRQ-safe.
Device Low Power (suspend) States
---------------------------------