When turning the screen off we could have 2 waiters on the
vsync condition: The main vsync waiter as well as one in
onScreenReleased(). We were only signaling the condition though,
so it it would be possible to wake onScreenReleased() without waking
the main vsync thread which would then be stuck in .wait().
We fix this by just using broadcast() when receiving a vsync event.
We also add a broadcast() to signal when the state of
mUseSoftwareVSync changes. This is important particularly for
the transition from hardware to software vsync because the main
vsync waiter might have observed mUseSoftwareVSync == false
and decided to block indefinitely pending a hardware vsync
signal that will never arrive.
Removed a potentially deadlocking wait for a signal in
onScreenReleased(). The function was trying to wait for the last
vsync event from the hardware to be delivered to clients but there
was no guarantee that another thread would signal it to wake up
again afterwards. (As far as I can tell, the only other other
thread that might wake it up at this point would be a client
application issuing a vsync request.) We don't really need to wait
here anyhow. It's enough to set the mUseSoftwareVSync flag,
wake up the thread loop and go. If there was a pending vsync
timestamp from the hardware, then the thread loop will grab
it and use it then start software vsync on the next iteration.
Bug: 6672102
Change-Id: I7c6abc23bb021d1dfc94f101bd3ce18e3a81a73e
vsync events were sometimes delivered to connected
client who didn't request them. this happened if
another client requested the delivery and that client
was first in the client list.
also fix the vsync test which didn't request any events as
well as DisplayEventReveiver documentation which was misleading
about the necessity to request vsync events.
Change-Id: Ie990fda3f337f8f0042745c4b2cde67936c45686
It is now possible to say:
dumpsys SurfaceFlinger --latency
to print latency information about all windows
dumpsys SurfaceFlinger --latency window-name
to print the latency stats of the specified window
for instance: dumpsys SurfaceFlinger --latency SurfaceView
The data consists of one line containing global stats, followed by
128 lines of tab separated timestamps in nanosecond.
The first line currently contains the refresh period in nanosecond.
Each 128 following line contains 3 timestamps, of respectively
the app draw time, the vsync timestamp just prior the call to set and
the timestamp of the call to set.
Change-Id: Ib6b6da1d7e2e6ba49c282bdbc0b56a7dc203343a
- add the ability to set the vsync delivery rate, when the rate is
set to N>1 (ie: receive every N vsync), SF process' is woken up for
all of vsync, but clients only see the every N events.
- add the concept of one-shot vsync events, with a call-back
to request the next one. currently the call-back is a binder IPC.
Change-Id: I09f71df0b0ba0d88ed997645e2e2497d553c9a1b
the deadlock would happen when the pipe became invalid and SF
trying to remove the connection from its list.
we know make sure to process events without holding a lock.
Change-Id: I39927ed8824fc7811e16db3c7608a2ebc72d9642
use gui/DisplayEvent to receive the events. Events are
dispatched through a unix pipe, so the API is compatible
with utils/Looper. see gui/DisplayEvent.h for more info.
Bug: 1475048
Change-Id: Ia720f64d1b950328b47b22c6a86042e481d35f09
Mathias Agopian