Make thresholds tuneable in the ddc

Add screen and ambient thresholds to the ddc. Use these values as a minimum required change, so that brightness can be more stable at lower light levels. Bug: 205683328 Test: adb shell dumpsys display Test: atest AutomaticBrightnessControllerTest Change-Id: I3af6d754899d75ed51964ed7ad140f1572ec41b0
2022-01-18 14:17:28 +00:00
parent 08d0c47646
commit 42ab279628
6 changed files with 186 additions and 15 deletions
--- a/services/core/java/com/android/server/display/DisplayDeviceConfig.java
+++ b/services/core/java/com/android/server/display/DisplayDeviceConfig.java
@@ -32,6 +32,7 @@ import android.view.DisplayAddress;

 import com.android.internal.R;
 import com.android.internal.display.BrightnessSynchronizer;
+import com.android.server.display.config.BrightnessThresholds;
 import com.android.server.display.config.Density;
 import com.android.server.display.config.DisplayConfiguration;
 import com.android.server.display.config.DisplayQuirks;
@@ -42,6 +43,7 @@ import com.android.server.display.config.Point;
 import com.android.server.display.config.RefreshRateRange;
 import com.android.server.display.config.SensorDetails;
 import com.android.server.display.config.ThermalStatus;
+import com.android.server.display.config.Thresholds;
 import com.android.server.display.config.XmlParser;

 import org.xmlpull.v1.XmlPullParserException;
@@ -130,6 +132,10 @@ public class DisplayDeviceConfig {
    private float mBrightnessRampSlowIncrease = Float.NaN;
    private int mAmbientHorizonLong = AMBIENT_LIGHT_LONG_HORIZON_MILLIS;
    private int mAmbientHorizonShort = AMBIENT_LIGHT_SHORT_HORIZON_MILLIS;
+    private float mScreenBrighteningMinThreshold = 0.0f;     // Retain behaviour as though there is
+    private float mScreenDarkeningMinThreshold = 0.0f;       // no minimum threshold for change in
+    private float mAmbientLuxBrighteningMinThreshold = 0.0f; // screen brightness or ambient
+    private float mAmbientLuxDarkeningMinThreshold = 0.0f;   // brightness.
    private Spline mBrightnessToBacklightSpline;
    private Spline mBacklightToBrightnessSpline;
    private Spline mBacklightToNitsSpline;
@@ -364,6 +370,22 @@ public class DisplayDeviceConfig {
        return mAmbientHorizonShort;
    }

+    public float getScreenBrighteningMinThreshold() {
+        return mScreenBrighteningMinThreshold;
+    }
+
+    public float getScreenDarkeningMinThreshold() {
+        return mScreenDarkeningMinThreshold;
+    }
+
+    public float getAmbientLuxBrighteningMinThreshold() {
+        return mAmbientLuxBrighteningMinThreshold;
+    }
+
+    public float getAmbientLuxDarkeningMinThreshold() {
+        return mAmbientLuxDarkeningMinThreshold;
+    }
+
    SensorData getAmbientLightSensor() {
        return mAmbientLightSensor;
    }
@@ -425,6 +447,10 @@ public class DisplayDeviceConfig {
                + ", mBrightnessRampSlowIncrease=" + mBrightnessRampSlowIncrease
                + ", mAmbientHorizonLong=" + mAmbientHorizonLong
                + ", mAmbientHorizonShort=" + mAmbientHorizonShort
+                + ", mScreenDarkeningMinThreshold=" + mScreenDarkeningMinThreshold
+                + ", mScreenBrighteningMinThreshold=" + mScreenBrighteningMinThreshold
+                + ", mAmbientLuxDarkeningMinThreshold=" + mAmbientLuxDarkeningMinThreshold
+                + ", mAmbientLuxBrighteningMinThreshold=" + mAmbientLuxBrighteningMinThreshold
                + ", mAmbientLightSensor=" + mAmbientLightSensor
                + ", mProximitySensor=" + mProximitySensor
                + ", mRefreshRateLimitations= " + Arrays.toString(mRefreshRateLimitations.toArray())
@@ -482,6 +508,7 @@ public class DisplayDeviceConfig {
                loadAmbientLightSensorFromDdc(config);
                loadProxSensorFromDdc(config);
                loadAmbientHorizonFromDdc(config);
+                loadBrightnessChangeThresholds(config);
            } else {
                Slog.w(TAG, "DisplayDeviceConfig file is null");
            }
@@ -865,6 +892,45 @@ public class DisplayDeviceConfig {
        }
    }

+    private void loadBrightnessChangeThresholds(DisplayConfiguration config) {
+        Thresholds displayBrightnessThresholds = config.getDisplayBrightnessChangeThresholds();
+        Thresholds ambientBrightnessThresholds = config.getAmbientBrightnessChangeThresholds();
+
+        if (displayBrightnessThresholds != null) {
+            BrightnessThresholds brighteningScreen =
+                    displayBrightnessThresholds.getBrighteningThresholds();
+            BrightnessThresholds darkeningScreen =
+                    displayBrightnessThresholds.getDarkeningThresholds();
+
+            final BigDecimal screenBrighteningThreshold = brighteningScreen.getMinimum();
+            final BigDecimal screenDarkeningThreshold = darkeningScreen.getMinimum();
+
+            if (screenBrighteningThreshold != null) {
+                mScreenBrighteningMinThreshold = screenBrighteningThreshold.floatValue();
+            }
+            if (screenDarkeningThreshold != null) {
+                mScreenDarkeningMinThreshold = screenDarkeningThreshold.floatValue();
+            }
+        }
+
+        if (ambientBrightnessThresholds != null) {
+            BrightnessThresholds brighteningAmbientLux =
+                    ambientBrightnessThresholds.getBrighteningThresholds();
+            BrightnessThresholds darkeningAmbientLux =
+                    ambientBrightnessThresholds.getDarkeningThresholds();
+
+            final BigDecimal ambientBrighteningThreshold = brighteningAmbientLux.getMinimum();
+            final BigDecimal ambientDarkeningThreshold =  darkeningAmbientLux.getMinimum();
+
+            if (ambientBrighteningThreshold != null) {
+                mAmbientLuxBrighteningMinThreshold = ambientBrighteningThreshold.floatValue();
+            }
+            if (ambientDarkeningThreshold != null) {
+                mAmbientLuxDarkeningMinThreshold = ambientDarkeningThreshold.floatValue();
+            }
+        }
+    }
+
    private @PowerManager.ThermalStatus int convertThermalStatus(ThermalStatus value) {
        if (value == null) {
            return PowerManager.THERMAL_STATUS_NONE;
--- a/services/core/java/com/android/server/display/DisplayPowerController.java
+++ b/services/core/java/com/android/server/display/DisplayPowerController.java
@@ -911,9 +911,14 @@ final class DisplayPowerController implements AutomaticBrightnessController.Call
                    com.android.internal.R.array.config_ambientDarkeningThresholds);
            int[] ambientThresholdLevels = resources.getIntArray(
                    com.android.internal.R.array.config_ambientThresholdLevels);
+            float ambientDarkeningMinThreshold =
+                    mDisplayDeviceConfig.getAmbientLuxDarkeningMinThreshold();
+            float ambientBrighteningMinThreshold =
+                    mDisplayDeviceConfig.getAmbientLuxBrighteningMinThreshold();
            HysteresisLevels ambientBrightnessThresholds = new HysteresisLevels(
                    ambientBrighteningThresholds, ambientDarkeningThresholds,
-                    ambientThresholdLevels);
+                    ambientThresholdLevels, ambientDarkeningMinThreshold,
+                    ambientBrighteningMinThreshold);

            int[] screenBrighteningThresholds = resources.getIntArray(
                    com.android.internal.R.array.config_screenBrighteningThresholds);
@@ -921,8 +926,13 @@ final class DisplayPowerController implements AutomaticBrightnessController.Call
                    com.android.internal.R.array.config_screenDarkeningThresholds);
            int[] screenThresholdLevels = resources.getIntArray(
                    com.android.internal.R.array.config_screenThresholdLevels);
+            float screenDarkeningMinThreshold =
+                    mDisplayDeviceConfig.getScreenDarkeningMinThreshold();
+            float screenBrighteningMinThreshold =
+                    mDisplayDeviceConfig.getScreenBrighteningMinThreshold();
            HysteresisLevels screenBrightnessThresholds = new HysteresisLevels(
-                    screenBrighteningThresholds, screenDarkeningThresholds, screenThresholdLevels);
+                    screenBrighteningThresholds, screenDarkeningThresholds, screenThresholdLevels,
+                    screenDarkeningMinThreshold, screenBrighteningMinThreshold);

            long brighteningLightDebounce = resources.getInteger(
                    com.android.internal.R.integer.config_autoBrightnessBrighteningLightDebounce);
--- a/services/core/java/com/android/server/display/HysteresisLevels.java
+++ b/services/core/java/com/android/server/display/HysteresisLevels.java
@@ -30,17 +30,13 @@ import java.util.Arrays;
 public class HysteresisLevels {
    private static final String TAG = "HysteresisLevels";

-    // Default hysteresis constraints for brightening or darkening.
-    // The recent value must have changed by at least this fraction relative to the
-    // current value before a change will be considered.
-    private static final float DEFAULT_BRIGHTENING_HYSTERESIS = 0.10f;
-    private static final float DEFAULT_DARKENING_HYSTERESIS = 0.20f;
-
    private static final boolean DEBUG = false;

    private final float[] mBrighteningThresholds;
    private final float[] mDarkeningThresholds;
    private final float[] mThresholdLevels;
+    private final float mMinDarkening;
+    private final float mMinBrightening;

    /**
     * Creates a {@code HysteresisLevels} object with the given equal-length
@@ -48,9 +44,12 @@ public class HysteresisLevels {
     * @param brighteningThresholds an array of brightening hysteresis constraint constants.
     * @param darkeningThresholds an array of darkening hysteresis constraint constants.
     * @param thresholdLevels a monotonically increasing array of threshold levels.
+     * @param minBrighteningThreshold the minimum value for which the brightening value needs to
+     *                                return.
+     * @param minDarkeningThreshold the minimum value for which the darkening value needs to return.
    */
    HysteresisLevels(int[] brighteningThresholds, int[] darkeningThresholds,
-            int[] thresholdLevels) {
+            int[] thresholdLevels, float minDarkeningThreshold, float minBrighteningThreshold) {
        if (brighteningThresholds.length != darkeningThresholds.length
                || darkeningThresholds.length != thresholdLevels.length + 1) {
            throw new IllegalArgumentException("Mismatch between hysteresis array lengths.");
@@ -58,6 +57,8 @@ public class HysteresisLevels {
        mBrighteningThresholds = setArrayFormat(brighteningThresholds, 1000.0f);
        mDarkeningThresholds = setArrayFormat(darkeningThresholds, 1000.0f);
        mThresholdLevels = setArrayFormat(thresholdLevels, 1.0f);
+        mMinDarkening = minDarkeningThreshold;
+        mMinBrightening = minBrighteningThreshold;
    }

    /**
@@ -65,11 +66,13 @@ public class HysteresisLevels {
     */
    public float getBrighteningThreshold(float value) {
        final float brightConstant = getReferenceLevel(value, mBrighteningThresholds);
-        final float brightThreshold = value * (1.0f + brightConstant);
+        float brightThreshold = value * (1.0f + brightConstant);
        if (DEBUG) {
            Slog.d(TAG, "bright hysteresis constant=" + brightConstant + ", threshold="
                    + brightThreshold + ", value=" + value);
        }
+
+        brightThreshold = Math.max(brightThreshold, value + mMinBrightening);
        return brightThreshold;
    }

@@ -78,12 +81,13 @@ public class HysteresisLevels {
     */
    public float getDarkeningThreshold(float value) {
        final float darkConstant = getReferenceLevel(value, mDarkeningThresholds);
-        final float darkThreshold = value * (1.0f - darkConstant);
+        float darkThreshold = value * (1.0f - darkConstant);
        if (DEBUG) {
            Slog.d(TAG, "dark hysteresis constant=: " + darkConstant + ", threshold="
                    + darkThreshold + ", value=" + value);
        }
-        return darkThreshold;
+        darkThreshold = Math.min(darkThreshold, value - mMinDarkening);
+        return Math.max(darkThreshold, 0.0f);
    }

    /**
--- a/services/core/xsd/display-device-config/display-device-config.xsd
+++ b/services/core/xsd/display-device-config/display-device-config.xsd
@@ -38,7 +38,8 @@
                    <xs:annotation name="nonnull"/>
                    <xs:annotation name="final"/>
                </xs:element>
-                <xs:element type="highBrightnessMode" name="highBrightnessMode" minOccurs="0" maxOccurs="1"/>
+                <xs:element type="highBrightnessMode" name="highBrightnessMode" minOccurs="0"
+                            maxOccurs="1"/>
                <xs:element type="displayQuirks" name="quirks" minOccurs="0" maxOccurs="1" />
                <xs:element type="nonNegativeDecimal" name="screenBrightnessRampFastDecrease">
                    <xs:annotation name="final"/>
@@ -67,6 +68,19 @@
                <xs:element type="xs:nonNegativeInteger" name="ambientLightHorizonShort">
                    <xs:annotation name="final"/>
                </xs:element>
+
+                <!-- Set of thresholds that dictate the change needed for screen brightness
+                adaptations -->
+                <xs:element type="thresholds" name="displayBrightnessChangeThresholds">
+                    <xs:annotation name="nonnull"/>
+                    <xs:annotation name="final"/>
+                </xs:element>
+                <!-- Set of thresholds that dictate the change needed for ambient brightness
+                adaptations -->
+                <xs:element type="thresholds" name="ambientBrightnessChangeThresholds">
+                    <xs:annotation name="nonnull"/>
+                    <xs:annotation name="final"/>
+                </xs:element>
            </xs:sequence>
        </xs:complexType>
    </xs:element>
@@ -81,7 +95,8 @@

    <xs:complexType name="highBrightnessMode">
        <xs:all>
-            <xs:element name="transitionPoint" type="nonNegativeDecimal" minOccurs="1" maxOccurs="1">
+            <xs:element name="transitionPoint" type="nonNegativeDecimal" minOccurs="1"
+                        maxOccurs="1">
                <xs:annotation name="nonnull"/>
                <xs:annotation name="final"/>
            </xs:element>
@@ -110,7 +125,8 @@

    <xs:complexType name="hbmTiming">
        <xs:all>
-            <xs:element name="timeWindowSecs" type="xs:nonNegativeInteger" minOccurs="1" maxOccurs="1">
+            <xs:element name="timeWindowSecs" type="xs:nonNegativeInteger" minOccurs="1"
+                        maxOccurs="1">
                <xs:annotation name="nonnull"/>
                <xs:annotation name="final"/>
            </xs:element>
@@ -216,5 +232,33 @@
                <xs:annotation name="final"/>
            </xs:element>
        </xs:sequence>
+      </xs:complexType>
+
+    <!-- Thresholds for brightness changes. -->
+    <xs:complexType name="thresholds">
+        <xs:sequence>
+            <!-- Brightening thresholds. -->
+            <xs:element name="brighteningThresholds" type="brightnessThresholds" minOccurs="0"
+                        maxOccurs="1" >
+                <xs:annotation name="nonnull"/>
+                <xs:annotation name="final"/>
+            </xs:element>
+            <!-- Darkening thresholds. -->
+            <xs:element name="darkeningThresholds" type="brightnessThresholds" minOccurs="0"
+                        maxOccurs="1" >
+                <xs:annotation name="nonnull"/>
+                <xs:annotation name="final"/>
+            </xs:element>
+        </xs:sequence>
    </xs:complexType>
+
+    <!-- Brightening and darkening minimum change thresholds. -->
+    <xs:complexType name="brightnessThresholds">
+        <!-- Minimum brightness change needed. -->
+        <xs:element name="minimum" type="nonNegativeDecimal" minOccurs="0" maxOccurs="1" >
+            <xs:annotation name="nonnull"/>
+            <xs:annotation name="final"/>
+        </xs:element>
+    </xs:complexType>
+
 </xs:schema>
--- a/services/core/xsd/display-device-config/schema/current.txt
+++ b/services/core/xsd/display-device-config/schema/current.txt
@@ -1,6 +1,12 @@
 // Signature format: 2.0
 package com.android.server.display.config {

+  public class BrightnessThresholds {
+    ctor public BrightnessThresholds();
+    method @NonNull public final java.math.BigDecimal getMinimum();
+    method public final void setMinimum(@NonNull java.math.BigDecimal);
+  }
+
  public class Density {
    ctor public Density();
    method @NonNull public final java.math.BigInteger getDensity();
@@ -18,9 +24,11 @@ package com.android.server.display.config {

  public class DisplayConfiguration {
    ctor public DisplayConfiguration();
+    method @NonNull public final com.android.server.display.config.Thresholds getAmbientBrightnessChangeThresholds();
    method public final java.math.BigInteger getAmbientLightHorizonLong();
    method public final java.math.BigInteger getAmbientLightHorizonShort();
    method @Nullable public final com.android.server.display.config.DensityMap getDensityMap();
+    method @NonNull public final com.android.server.display.config.Thresholds getDisplayBrightnessChangeThresholds();
    method public com.android.server.display.config.HighBrightnessMode getHighBrightnessMode();
    method public final com.android.server.display.config.SensorDetails getLightSensor();
    method public final com.android.server.display.config.SensorDetails getProxSensor();
@@ -31,9 +39,11 @@ package com.android.server.display.config {
    method public final java.math.BigDecimal getScreenBrightnessRampFastIncrease();
    method public final java.math.BigDecimal getScreenBrightnessRampSlowDecrease();
    method public final java.math.BigDecimal getScreenBrightnessRampSlowIncrease();
+    method public final void setAmbientBrightnessChangeThresholds(@NonNull com.android.server.display.config.Thresholds);
    method public final void setAmbientLightHorizonLong(java.math.BigInteger);
    method public final void setAmbientLightHorizonShort(java.math.BigInteger);
    method public final void setDensityMap(@Nullable com.android.server.display.config.DensityMap);
+    method public final void setDisplayBrightnessChangeThresholds(@NonNull com.android.server.display.config.Thresholds);
    method public void setHighBrightnessMode(com.android.server.display.config.HighBrightnessMode);
    method public final void setLightSensor(com.android.server.display.config.SensorDetails);
    method public final void setProxSensor(com.android.server.display.config.SensorDetails);
@@ -121,6 +131,14 @@ package com.android.server.display.config {
    enum_constant public static final com.android.server.display.config.ThermalStatus shutdown;
  }

+  public class Thresholds {
+    ctor public Thresholds();
+    method @NonNull public final com.android.server.display.config.BrightnessThresholds getBrighteningThresholds();
+    method @NonNull public final com.android.server.display.config.BrightnessThresholds getDarkeningThresholds();
+    method public final void setBrighteningThresholds(@NonNull com.android.server.display.config.BrightnessThresholds);
+    method public final void setDarkeningThresholds(@NonNull com.android.server.display.config.BrightnessThresholds);
+  }
+
  public class XmlParser {
    ctor public XmlParser();
    method public static com.android.server.display.config.DisplayConfiguration read(java.io.InputStream) throws javax.xml.datatype.DatatypeConfigurationException, java.io.IOException, org.xmlpull.v1.XmlPullParserException;
--- a/services/tests/servicestests/src/com/android/server/display/AutomaticBrightnessControllerTest.java
+++ b/services/tests/servicestests/src/com/android/server/display/AutomaticBrightnessControllerTest.java
@@ -391,4 +391,33 @@ public class AutomaticBrightnessControllerTest {
        listener.onSensorChanged(TestUtils.createSensorEvent(lightSensor, 0));
        assertEquals(0.0f, mController.getAmbientLux(), EPSILON);
    }
+
+    @Test
+    public void testHysteresisLevels() {
+        int[] ambientBrighteningThresholds = {100, 200};
+        int[] ambientDarkeningThresholds = {400, 500};
+        int[] ambientThresholdLevels = {500};
+        float ambientDarkeningMinChangeThreshold = 3.0f;
+        float ambientBrighteningMinChangeThreshold = 1.5f;
+        HysteresisLevels hysteresisLevels = new HysteresisLevels(ambientBrighteningThresholds,
+                ambientDarkeningThresholds, ambientThresholdLevels,
+                ambientDarkeningMinChangeThreshold, ambientBrighteningMinChangeThreshold);
+
+        // test low, activate minimum change thresholds.
+        assertEquals(1.5f, hysteresisLevels.getBrighteningThreshold(0.0f), EPSILON);
+        assertEquals(0f, hysteresisLevels.getDarkeningThreshold(0.0f), EPSILON);
+        assertEquals(1f, hysteresisLevels.getDarkeningThreshold(4.0f), EPSILON);
+
+        // test max
+        assertEquals(12000f, hysteresisLevels.getBrighteningThreshold(10000.0f), EPSILON);
+        assertEquals(5000f, hysteresisLevels.getDarkeningThreshold(10000.0f), EPSILON);
+
+        // test just below threshold
+        assertEquals(548.9f, hysteresisLevels.getBrighteningThreshold(499f), EPSILON);
+        assertEquals(299.4f, hysteresisLevels.getDarkeningThreshold(499f), EPSILON);
+
+        // test at (considered above) threshold
+        assertEquals(600f, hysteresisLevels.getBrighteningThreshold(500f), EPSILON);
+        assertEquals(250f, hysteresisLevels.getDarkeningThreshold(500f), EPSILON);
+    }
 }