The major goal of this rewrite is to make it easier to implement
power management policies correctly. According, the new
implementation primarily uses state-based rather than event-based
triggers for applying changes to the current power state.
For example, when an application requests that the proximity
sensor be used to manage the screen state (by way of a wake lock),
the power manager makes note of the fact that the set of
wake locks changed. Then it executes a common update function
that recalculates the entire state, first looking at wake locks,
then considering user activity, and eventually determining whether
the screen should be turned on or off. At this point it may
make a request to a component called the DisplayPowerController
to asynchronously update the display's powe state. Likewise,
DisplayPowerController makes note of the updated power request
and schedules its own update function to figure out what needs
to be changed.
The big benefit of this approach is that it's easy to mutate
multiple properties of the power state simultaneously then
apply their joint effects together all at once. Transitions
between states are detected and resolved by the update in
a consistent manner.
The new power manager service has is implemented as a set of
loosely coupled components. For the most part, information
only flows one way through these components (by issuing a
request to that component) although some components support
sending a message back to indicate when the work has been
completed. For example, the DisplayPowerController posts
a callback runnable asynchronously to tell the PowerManagerService
when the display is ready. An important feature of this
approach is that each component neatly encapsulates its
state and maintains its own invariants. Moreover, we do
not need to worry about deadlocks or awkward mutual exclusion
semantics because most of the requests are asynchronous.
The benefits of this design are especially apparent in
the implementation of the screen on / off and brightness
control animations which are able to take advantage of
framework features like properties, ObjectAnimator
and Choreographer.
The screen on / off animation is now the responsibility
of the power manager (instead of surface flinger). This change
makes it much easier to ensure that the animation is properly
coordinated with other power state changes and eliminates
the cause of race conditions in the older implementation.
The because of the userActivity() function has been changed
so that it never wakes the device from sleep. This change
removes ambiguity around forcing or disabling user activity
for various purposes. To wake the device, use wakeUp().
To put it to sleep, use goToSleep(). Simple.
The power manager service interface and API has been significantly
simplified and consolidated. Also fixed some inconsistencies
related to how the minimum and maximum screen brightness setting
was presented in brightness control widgets and enforced behind
the scenes.
At present the following features are implemented:
- Wake locks.
- User activity.
- Wake up / go to sleep.
- Power state broadcasts.
- Battery stats and event log notifications.
- Dreams.
- Proximity screen off.
- Animated screen on / off transitions.
- Auto-dimming.
- Auto-brightness control for the screen backlight with
different timeouts for ramping up versus ramping down.
- Auto-on when plugged or unplugged.
- Stay on when plugged.
- Device administration maximum user activity timeout.
- Application controlled brightness via window manager.
The following features are not yet implemented:
- Reduced user activity timeout for the key guard.
- Reduced user activity timeout for the phone application.
- Coordinating screen on barriers with the window manager.
- Preventing auto-rotation during power state changes.
- Auto-brightness adjustment setting (feature was disabled
in previous version of the power manager service pending
an improved UI design so leaving it out for now).
- Interpolated brightness control (a proposed new scheme
for more compactly specifying auto-brightness levels
in config.xml).
- Button / keyboard backlight control.
- Change window manager to associated WorkSource with
KEEP_SCREEN_ON_FLAG wake lock instead of talking
directly to the battery stats service.
- Optionally support animating screen brightness when
turning on/off instead of playing electron beam animation
(config_animateScreenLights).
Change-Id: I1d7a52e98f0449f76d70bf421f6a7f245957d1d7
Normally the ValueAnimator scale factor is applied the first
time a ViewRootImpl window session is created but that may
be too late for animators created by system services that
start early in the boot process. So set the scale factor
immediately whenever the setting changes.
Also make ValueAnimator.getDurationScale() accessible (but @hide)
for custom animators that want to apply the same scale to
their animations.
Change-Id: I0f5a750ab5b014f63848445435d8dca86f2a7ada
We don't want these messages to get blocked by UI traversals.
Added a convenience for creating Handlers that always send
asynchronous messages.
Change-Id: Id568e87fcb8b169e8c52c5fe1dc76a4a5771570b
This allows you to, say, make a Context whose configuration
is set to a different density than the actual density of the device.
The main API is Context.createConfigurationContext(). There is
also a new API on ContextThemeWrapper that allows you to apply
an override context before its resources are retrieved, which
addresses some feature requests from developers to be able to
customize the context their app is running in.
Change-Id: I88364986660088521e24b567e2fda22fb7042819
Lockscreen and statusbar now launch the intent on the current user.
Make sure that the intent resolution is made to the package manager
for the specific user, as the app could have been disabled for that
user or may have an alternative app installed.
Change-Id: I93b0f972d6c7e8880b146da83dc3d08a68fe7e51
- Fixes a strict mode violation, defers file validity checks
to when the engine starts synthesizing audio.
- Fixes some log spam when done() is called twice.
bug:6215680
bug:5415258
Change-Id: I4001be848b5208422d4091b7398e94ed311c649f
Will be seen when createStreamingAudioTrack() returns null,
which will happen if the audioflinger / audiomanager are unhealthy.
Also removes some confusing synchronization from this class.
bug:6636401
Change-Id: Iaf68a305665b7bc973898145e9cd1563e2569a2b
