Mitigation of incorrect maxNumSpatialStreamDevice.

Many android devices will set maxNumSpatialStreamDevice incorrectly to 8
due to a WLAN driver bug. The bug fix is being ported but not expected
to be applied to all affected products on time. As a mitigation method,
add overriding enable flag and value in config overlay file to override
maxNumSpatialStreamDevice to a correct value before the bug fix is
completely populated. The enable flag is set by default with a default
overriding value of 2. Final settings can be configured per device.

Bug: 148982542
Test: atest com.android.server.wifi
Change-Id: I7b95a0b7f5685ab8b841113ff7136723d8b04250

5 files changed, 78 insertions, 3 deletions

diff --git a/service/java/com/android/server/wifi/ThroughputPredictor.java b/service/java/com/android/server/wifi/ThroughputPredictor.java
index e381b2b14..9a33863e4 100644
--- a/service/java/com/android/server/wifi/ThroughputPredictor.java
+++ b/service/java/com/android/server/wifi/ThroughputPredictor.java
@@ -20,12 +20,15 @@ import static com.android.server.wifi.util.InformationElementUtil.BssLoad.MAX_CH
 import static com.android.server.wifi.util.InformationElementUtil.BssLoad.MIN_CHANNEL_UTILIZATION;
 
 import android.annotation.NonNull;
+import android.content.Context;
 import android.net.wifi.ScanResult;
 import android.net.wifi.WifiAnnotations.WifiStandard;
 import android.net.wifi.WifiInfo;
 import android.net.wifi.nl80211.DeviceWiphyCapabilities;
 import android.util.Log;
 
+import com.android.wifi.resources.R;
+
 /**
  * A class that predicts network throughput based on RSSI, channel utilization, channel width,
  * WiFi standard (PHY/MAC mode), Nss and other radio information.
@@ -97,6 +100,12 @@ public class ThroughputPredictor {
     private static final int MAX_NUM_SPATIAL_STREAM_11N = 4;
     private static final int MAX_NUM_SPATIAL_STREAM_LEGACY = 1;
 
+    private final Context mContext;
+
+    ThroughputPredictor(Context context) {
+        mContext = context;
+    }
+
     /**
      * Enable/Disable verbose logging.
      *
@@ -177,6 +186,12 @@ public class ThroughputPredictor {
         int maxNumSpatialStreamDevice = Math.min(deviceCapabilities.getMaxNumberTxSpatialStreams(),
                 deviceCapabilities.getMaxNumberRxSpatialStreams());
 
+        if (mContext.getResources().getBoolean(
+                R.bool.config_wifiFrameworkMaxNumSpatialStreamDeviceOverrideEnable)) {
+            maxNumSpatialStreamDevice = mContext.getResources().getInteger(
+                    R.integer.config_wifiFrameworkMaxNumSpatialStreamDeviceOverrideValue);
+        }
+
         int maxNumSpatialStream = Math.min(maxNumSpatialStreamDevice, maxNumSpatialStreamAp);
 
         // Get minimum standard support between device and AP
diff --git a/service/java/com/android/server/wifi/WifiInjector.java b/service/java/com/android/server/wifi/WifiInjector.java
index 594008975..c6692d2fc 100644
--- a/service/java/com/android/server/wifi/WifiInjector.java
+++ b/service/java/com/android/server/wifi/WifiInjector.java
@@ -286,7 +286,7 @@ public class WifiInjector {
                 mContext.getSystemService(ActivityManager.class).isLowRamDevice() ? 256 : 512);
         mScoringParams = new ScoringParams(mContext);
         mWifiMetrics.setScoringParams(mScoringParams);
-        mThroughputPredictor = new ThroughputPredictor();
+        mThroughputPredictor = new ThroughputPredictor(mContext);
         mWifiNetworkSelector = new WifiNetworkSelector(mContext, mWifiScoreCard, mScoringParams,
                 mWifiConfigManager, mClock, mConnectivityLocalLog, mWifiMetrics, mWifiNative,
                 mThroughputPredictor);
diff --git a/service/res/values/config.xml b/service/res/values/config.xml
index 4d351b105..dd5b75f71 100644
--- a/service/res/values/config.xml
+++ b/service/res/values/config.xml
@@ -36,6 +36,13 @@
            be checked via NL80211 interface -->
     <bool translatable="false" name="config_wifi11axSupportOverride">false</bool>
 
+    <!-- Indicates whether to enable overriding the max number of spatial stream supported by the device
+         If true, config_wifiFrameworkMaxNumSpatialStreamDeviceOverrideValue
+         will be used to override the max number of spatial stream supported by the device.
+         If false, it will be left to WifiCond to derive the value from NL80211 interface -->
+    <bool translatable="false" name="config_wifiFrameworkMaxNumSpatialStreamDeviceOverrideEnable">true</bool>
+    <integer translatable="false" name="config_wifiFrameworkMaxNumSpatialStreamDeviceOverrideValue">2</integer>
+
     <!-- Boolean indicating whether 802.11r Fast BSS Transition is enabled on this platform -->
     <bool translatable="false" name="config_wifi_fast_bss_transition_enabled">false</bool>
 
diff --git a/service/res/values/overlayable.xml b/service/res/values/overlayable.xml
index 7244911af..bc2c06cc3 100644
--- a/service/res/values/overlayable.xml
+++ b/service/res/values/overlayable.xml
@@ -23,6 +23,8 @@
           <item type="bool" name="config_wifi5ghzSupport" />
           <item type="bool" name="config_wifi6ghzSupport" />
           <item type="bool" name="config_wifi11axSupportOverride" />
+          <item type="bool" name="config_wifiFrameworkMaxNumSpatialStreamDeviceOverrideEnable" />
+          <item type="integer" name="config_wifiFrameworkMaxNumSpatialStreamDeviceOverrideValue" />
           <item type="bool" name="config_wifi_fast_bss_transition_enabled" />
           <item type="string" name="config_wifi_p2p_device_type" />
           <item type="bool" name="config_wifi_background_scan_support" />
diff --git a/tests/wifitests/src/com/android/server/wifi/ThroughputPredictorTest.java b/tests/wifitests/src/com/android/server/wifi/ThroughputPredictorTest.java
index aa3010a33..f8b0586ee 100644
--- a/tests/wifitests/src/com/android/server/wifi/ThroughputPredictorTest.java
+++ b/tests/wifitests/src/com/android/server/wifi/ThroughputPredictorTest.java
@@ -24,16 +24,20 @@ import static org.junit.Assert.assertEquals;
 import static org.mockito.Mockito.validateMockitoUsage;
 import static org.mockito.Mockito.when;
 
+import android.content.Context;
 import android.net.wifi.ScanResult;
 import android.net.wifi.nl80211.DeviceWiphyCapabilities;
 
 import androidx.test.filters.SmallTest;
 
+import com.android.wifi.resources.R;
+
 import org.junit.After;
 import org.junit.Before;
 import org.junit.Test;
 import org.mockito.Mock;
 import org.mockito.MockitoAnnotations;
+import org.mockito.Spy;
 
 /**
  * Unit tests for {@link com.android.server.wifi.ThroughputPredictor}.
@@ -41,7 +45,12 @@ import org.mockito.MockitoAnnotations;
 @SmallTest
 public class ThroughputPredictorTest extends WifiBaseTest {
     @Mock private DeviceWiphyCapabilities mDeviceCapabilities;
-
+    @Mock private Context mContext;
+    // For simulating the resources, we use a Spy on a MockResource
+    // (which is really more of a stub than a mock, in spite if its name).
+    // This is so that we get errors on any calls that we have not explicitly set up.
+    @Spy
+    private MockResources mResource = new MockResources();
     ThroughputPredictor mThroughputPredictor;
     WifiNative.ConnectionCapabilities mConnectionCap = new WifiNative.ConnectionCapabilities();
 
@@ -67,7 +76,14 @@ public class ThroughputPredictorTest extends WifiBaseTest {
         when(mDeviceCapabilities.getMaxNumberTxSpatialStreams()).thenReturn(2);
         when(mDeviceCapabilities.getMaxNumberRxSpatialStreams()).thenReturn(2);
 
-        mThroughputPredictor = new ThroughputPredictor();
+        when(mResource.getBoolean(
+                R.bool.config_wifiFrameworkMaxNumSpatialStreamDeviceOverrideEnable))
+                .thenReturn(false);
+        when(mResource.getInteger(
+                R.integer.config_wifiFrameworkMaxNumSpatialStreamDeviceOverrideValue))
+                .thenReturn(2);
+        when(mContext.getResources()).thenReturn(mResource);
+        mThroughputPredictor = new ThroughputPredictor(mContext);
     }
 
     /** Cleans up test. */
@@ -113,6 +129,21 @@ public class ThroughputPredictorTest extends WifiBaseTest {
     }
 
     @Test
+    public void verifyHighRssiMinChannelUtilizationAc5g80Mhz2ssOverriddenTo1ss() {
+        when(mResource.getBoolean(
+                R.bool.config_wifiFrameworkMaxNumSpatialStreamDeviceOverrideEnable))
+                .thenReturn(true);
+        when(mResource.getInteger(
+                R.integer.config_wifiFrameworkMaxNumSpatialStreamDeviceOverrideValue))
+                .thenReturn(1);
+        int predictedThroughputMbps = mThroughputPredictor.predictThroughput(mDeviceCapabilities,
+                ScanResult.WIFI_STANDARD_11AC, ScanResult.CHANNEL_WIDTH_80MHZ, 0, 5180, 2,
+                MIN_CHANNEL_UTILIZATION, 50, false);
+
+        assertEquals(433, predictedThroughputMbps);
+    }
+
+    @Test
     public void verifyHighRssiMinChannelUtilizationAx5g160Mhz4ss() {
         when(mDeviceCapabilities.isWifiStandardSupported(ScanResult.WIFI_STANDARD_11AX))
                 .thenReturn(true);
@@ -129,6 +160,26 @@ public class ThroughputPredictorTest extends WifiBaseTest {
     }
 
     @Test
+    public void verifyHighRssiMinChannelUtilizationAx5g160Mhz4ssOverriddenTo2ss() {
+        when(mResource.getBoolean(
+                R.bool.config_wifiFrameworkMaxNumSpatialStreamDeviceOverrideEnable))
+                .thenReturn(true);
+        when(mDeviceCapabilities.isWifiStandardSupported(ScanResult.WIFI_STANDARD_11AX))
+                .thenReturn(true);
+        when(mDeviceCapabilities.isChannelWidthSupported(ScanResult.CHANNEL_WIDTH_160MHZ))
+                .thenReturn(true);
+        when(mDeviceCapabilities.getMaxNumberTxSpatialStreams()).thenReturn(4);
+        when(mDeviceCapabilities.getMaxNumberRxSpatialStreams()).thenReturn(4);
+
+        int predictedThroughputMbps = mThroughputPredictor.predictThroughput(mDeviceCapabilities,
+                ScanResult.WIFI_STANDARD_11AX, ScanResult.CHANNEL_WIDTH_160MHZ, 0, 5180, 4,
+                MIN_CHANNEL_UTILIZATION, INVALID, false);
+
+        assertEquals(2401, predictedThroughputMbps);
+    }
+
+
+    @Test
     public void verifyMidRssiMinChannelUtilizationAc5g80Mhz2ss() {
         int predictedThroughputMbps = mThroughputPredictor.predictThroughput(mDeviceCapabilities,
                 ScanResult.WIFI_STANDARD_11AC, ScanResult.CHANNEL_WIDTH_80MHZ, -50, 5180, 2,