add adb hooks for tweaking RSSI poll frequency

One of the significant power draws, when the
screen is on, is the periodic RSSI poll (and,
presumably, the associated link-layer stats
fetch).

Given this, we want to experiment with different
RSSI poll intervals, to balance power vs.
whatever benefit the RSSI / link-layer stats
provide.

So add adb commands which let a user get and
set the RSSI poll frequency.

Bug: 38342148
Test: tests/wifitests/runtest.sh (on bullhead)
Test: manual (see below)

1. adb root
2. adb shell cmd wifi get-poll-rssi-interval-msecs
   WifiStateMachine.mPollRssiIntervalMsecs = 3000
3. turn on screen, wait 15 seconds
4. adb shell dumpsys wifi | grep CMD_RSSI_POLL
   -> expect one line like the following, every 3 seconds
    rec[80]: time=06-06 23:36:18.201 processed=L2ConnectedState org=ConnectedState dest=<null> what=131155(0x20053) !CMD_RSSI_POLL rt=618277/618277 4 0 "GoogleGuest" 9c:1c:12:e8:70:f2 rssi=-59 f=5500 sc=56 link=300 tx=0.0, 0.0, 0.0  rx=0.0 bcn=4463 [on:3085 tx:0 rx:3 period:111] from screen [on:25363 period:27771] score=56
5. adb shell cmd wifi set-poll-rssi-interval-msecs 10000
6. turn on screen, wait 30 secods
7. adb shell dumpsys wifi | grep CMD_RSSI_POLL
   -> expect one line like the following, every 10 seconds
    rec[104]: time=06-06 23:37:40.921 processed=L2ConnectedState org=ConnectedState dest=<null> what=131155(0x20053) CMD_RSSI_POLL rt=700997/700997 6 0 "GoogleGuest" 9c:1c:12:e8:70:f2 rssi=-62 f=5500 sc=56 link=270 tx=0.0, 0.0, 0.0  rx=0.0 bcn=4665 [on:0 tx:0 rx:0 period:1] from screen [on:0 period:3162]
8. adb shell cmd wifi set-poll-rssi-interval-msecs 0
   -> Invalid argument to 'set-poll-rssi-interval-msecs' - must be a positive integer
9. adb shell cmd wifi set-poll-rssi-interval-msecs not-a-number
   -> Invalid argument to 'set-poll-rssi-interval-msecs' - must be a positive integer

Change-Id: Ibb2268cef81ef986fd71f848e889a4d7a94b901d

2 files changed, 43 insertions, 5 deletions

diff --git a/service/java/com/android/server/wifi/WifiShellCommand.java b/service/java/com/android/server/wifi/WifiShellCommand.java
index fc153d1fe..f4db178a8 100644
--- a/service/java/com/android/server/wifi/WifiShellCommand.java
+++ b/service/java/com/android/server/wifi/WifiShellCommand.java
@@ -75,6 +75,30 @@ public class WifiShellCommand extends ShellCommand {
                     pw.println("IPREACH_DISCONNECT state is "
                             + mStateMachine.getIpReachabilityDisconnectEnabled());
                     return 0;
+                case "set-poll-rssi-interval-msecs":
+                    int newPollIntervalMsecs;
+                    try {
+                        newPollIntervalMsecs = Integer.parseInt(getNextArgRequired());
+                    } catch (NumberFormatException e) {
+                        pw.println(
+                                "Invalid argument to 'set-poll-rssi-interval-msecs' "
+                                        + "- must be a positive integer");
+                        return -1;
+                    }
+
+                    if (newPollIntervalMsecs < 1) {
+                        pw.println(
+                                "Invalid argument to 'set-poll-rssi-interval-msecs' "
+                                        + "- must be a positive integer");
+                        return -1;
+                    }
+
+                    mStateMachine.setPollRssiIntervalMsecs(newPollIntervalMsecs);
+                    return 0;
+                case "get-poll-rssi-interval-msecs":
+                    pw.println("WifiStateMachine.mPollRssiIntervalMsecs = "
+                            + mStateMachine.getPollRssiIntervalMsecs());
+                    return 0;
                 default:
                     return handleDefaultCommands(cmd);
             }
@@ -104,6 +128,10 @@ public class WifiShellCommand extends ShellCommand {
         pw.println("    Sets whether CMD_IP_REACHABILITY_LOST events should trigger disconnects.");
         pw.println("  get-ipreach-disconnect");
         pw.println("    Gets setting of CMD_IP_REACHABILITY_LOST events triggering disconnects.");
+        pw.println("  set-poll-rssi-interval-msecs <int>");
+        pw.println("    Sets the interval between RSSI polls to <int> milliseconds.");
+        pw.println("  get-poll-rssi-interval-msecs");
+        pw.println("    Gets current interval between RSSI polls, in milliseconds.");
         pw.println();
     }
 }
diff --git a/service/java/com/android/server/wifi/WifiStateMachine.java b/service/java/com/android/server/wifi/WifiStateMachine.java
index 06da92545..89675b62d 100644
--- a/service/java/com/android/server/wifi/WifiStateMachine.java
+++ b/service/java/com/android/server/wifi/WifiStateMachine.java
@@ -284,6 +284,8 @@ public class WifiStateMachine extends StateMachine implements WifiNative.WifiRss
     private boolean testNetworkDisconnect = false;
 
     private boolean mEnableRssiPolling = false;
+    // Accessed via Binder thread ({get,set}PollRssiIntervalMsecs), and WifiStateMachine thread.
+    private volatile int mPollRssiIntervalMsecs = DEFAULT_POLL_RSSI_INTERVAL_MSECS;
     private int mRssiPollToken = 0;
     /* 3 operational states for STA operation: CONNECT_MODE, SCAN_ONLY_MODE, SCAN_ONLY_WIFI_OFF_MODE
     * In CONNECT_MODE, the STA can scan and connect to an access point
@@ -311,7 +313,7 @@ public class WifiStateMachine extends StateMachine implements WifiNative.WifiRss
      * Interval in milliseconds between polling for RSSI
      * and linkspeed information
      */
-    private static final int POLL_RSSI_INTERVAL_MSECS = 3000;
+    private static final int DEFAULT_POLL_RSSI_INTERVAL_MSECS = 3000;
 
     /**
      * Interval in milliseconds between receiving a disconnect event
@@ -379,6 +381,14 @@ public class WifiStateMachine extends StateMachine implements WifiNative.WifiRss
     private long mLastDriverRoamAttempt = 0;
     private WifiConfiguration targetWificonfiguration = null;
 
+    int getPollRssiIntervalMsecs() {
+        return mPollRssiIntervalMsecs;
+    }
+
+    void setPollRssiIntervalMsecs(int newPollIntervalMsecs) {
+        mPollRssiIntervalMsecs = newPollIntervalMsecs;
+    }
+
     /**
      * Method to clear {@link #mTargetRoamBSSID} and reset the the current connected network's
      * bssid in wpa_supplicant after a roam/connect attempt.
@@ -5709,8 +5719,8 @@ public class WifiStateMachine extends StateMachine implements WifiNative.WifiRss
                                     mWifiInfo, mNetworkAgent, mAggressiveHandover,
                                     mWifiMetrics);
                         }
-                        sendMessageDelayed(obtainMessage(CMD_RSSI_POLL,
-                                mRssiPollToken, 0), POLL_RSSI_INTERVAL_MSECS);
+                        sendMessageDelayed(obtainMessage(CMD_RSSI_POLL, mRssiPollToken, 0),
+                                mPollRssiIntervalMsecs);
                         if (mVerboseLoggingEnabled) sendRssiChangeBroadcast(mWifiInfo.getRssi());
                     } else {
                         // Polling has completed
@@ -5727,8 +5737,8 @@ public class WifiStateMachine extends StateMachine implements WifiNative.WifiRss
                     if (mEnableRssiPolling) {
                         // First poll
                         fetchRssiLinkSpeedAndFrequencyNative();
-                        sendMessageDelayed(obtainMessage(CMD_RSSI_POLL,
-                                mRssiPollToken, 0), POLL_RSSI_INTERVAL_MSECS);
+                        sendMessageDelayed(obtainMessage(CMD_RSSI_POLL, mRssiPollToken, 0),
+                                mPollRssiIntervalMsecs);
                     }
                     break;
                 case WifiManager.RSSI_PKTCNT_FETCH: