blob: f7c9c7d94628302d45e11a8c25b6bbc59bcb221e (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
|
/*
* Copyright (C) 2012 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.android.server.power;
import com.android.server.LightsService;
import java.util.concurrent.Executor;
/**
* Sets the value of a light asynchronously.
*
* This is done to avoid blocking the looper on devices for which
* setting the backlight brightness is especially slow.
*/
final class PhotonicModulator {
private static final int UNKNOWN_LIGHT_VALUE = -1;
private final Object mLock = new Object();
private final LightsService.Light mLight;
private final Executor mExecutor;
private final SuspendBlocker mSuspendBlocker;
private boolean mPendingChange;
private int mPendingLightValue;
private int mActualLightValue;
public PhotonicModulator(Executor executor, LightsService.Light light,
SuspendBlocker suspendBlocker) {
mExecutor = executor;
mLight = light;
mSuspendBlocker = suspendBlocker;
mPendingLightValue = UNKNOWN_LIGHT_VALUE;
mActualLightValue = UNKNOWN_LIGHT_VALUE;
}
/**
* Asynchronously sets the backlight brightness.
*
* @param lightValue The new light value, from 0 to 255.
*/
public void setBrightness(int lightValue) {
synchronized (mLock) {
if (lightValue != mPendingLightValue) {
mPendingLightValue = lightValue;
if (!mPendingChange) {
mPendingChange = true;
mSuspendBlocker.acquire();
mExecutor.execute(mTask);
}
}
}
}
private final Runnable mTask = new Runnable() {
@Override
public void run() {
for (;;) {
final int newLightValue;
synchronized (mLock) {
newLightValue = mPendingLightValue;
if (newLightValue == mActualLightValue) {
mSuspendBlocker.release();
mPendingChange = false;
return;
}
mActualLightValue = newLightValue;
}
mLight.setBrightness(newLightValue);
}
}
};
}
|
