SamsungQualcommUiccRIL: use signalstrength value instead of # of bars

  * Math error in GSM level calculation gave high probability that 4
    Samsung bars would be shown as 3 AOSP bars.
  * Samsung sends # of bars in the signalstrength field of GSM and LTE,
    indexes 0 and 7. But this is on a 0-5 scale where AOSP uses 0-4 scale.
    The cutoff points for the bins are also different. Because of this
    confusion, just pass the measured signalstrength to the framework
    instead of computing signalstrength based on # of Samsung bars.
  * For debug and experimentation, Samsung's bar method can be enabled
    by setting telephony.sends_barcount=true

Change-Id: I8238af83f3a597b32eb99f42c71cbc263ad5bc82

1 files changed, 45 insertions, 11 deletions

diff --git a/telephony/java/com/android/internal/telephony/SamsungQualcommUiccRIL.java b/telephony/java/com/android/internal/telephony/SamsungQualcommUiccRIL.java
index c45ab19..2c942ea 100644
--- a/telephony/java/com/android/internal/telephony/SamsungQualcommUiccRIL.java
+++ b/telephony/java/com/android/internal/telephony/SamsungQualcommUiccRIL.java
@@ -38,6 +38,9 @@ public class SamsungQualcommUiccRIL extends QualcommSharedRIL implements Command
     boolean RILJ_LOGV = true;
     boolean RILJ_LOGD = true;
 
+    public static final int INVALID_SNR = 0x7fffffff;
+    private boolean mSignalbarCount = SystemProperties.getBoolean("ro.telephony.sends_barcount", false);
+
     public SamsungQualcommUiccRIL(Context context, int networkMode, int cdmaSubscription) {
         super(context, networkMode, cdmaSubscription);
     }
@@ -225,18 +228,29 @@ public class SamsungQualcommUiccRIL extends QualcommSharedRIL implements Command
         for (int i = 0 ; i < numInts ; i++) {
             response[i] = p.readInt();
         }
+        Log.d(LOG_TAG, "responseSignalStength BEFORE: mode=" + (mSignalbarCount ? "bars" : "raw") +
+            " gsmDbm=" + response[0] + " gsmEcio=" + response[1] +
+            " lteSignalStrength=" + response[7] + " lteRsrp=" + response[8] + " lteRsrq=" + response[9] +
+            " lteRssnr=" + response[10] + " lteCqi=" + response[11]);
 
         // RIL_GW_SignalStrength
-        boolean mSignalbarCount = SystemProperties.getBoolean("telephony.sends_barcount", true);
-        if(mSignalbarCount) {
+        if (mSignalbarCount) {
             //Samsung sends the count of bars that should be displayed instead of
             //a real signal strength
-            response[0] = ((response[0] & 0xFF00) >> 8) * 3; //gsmDbm
-            if ((response[0] > 0) && (response[0] != 99)) {
-                response[0]--;   // correct down by 1 dBm to match stock's behavior
+            int num_bars = (response[0] & 0xff00) >> 8;
+
+            // Translate number of bars into something SignalStrength.java can understand
+            switch (num_bars) {
+                case 0  : response[0] = 1;     break; // map to 0 bars
+                case 1  : response[0] = 3;     break; // map to 1 bar
+                case 2  : response[0] = 5;     break; // map to 2 bars
+                case 3  : response[0] = 8;     break; // map to 3 bars
+                case 4  : response[0] = 12;    break; // map to 4 bars
+                case 5  : response[0] = 15;    break; // map to 4 bars but give an extra 10 dBm
+                default : response[0] &= 0xff; break; // no idea; just pass value through
             }
         } else {
-            response[0] = response[0] & 0xFF; //gsmDbm
+            response[0] &= 0xff; //gsmDbm
         }
         response[1] = -1; // gsmEcio
 
@@ -253,15 +267,35 @@ public class SamsungQualcommUiccRIL extends QualcommSharedRIL implements Command
         if (response[7] == 99) {
             // If LTE is not enabled, clear LTE results
             // 7-11 must be -1 for GSM signal strength to be used (see frameworks/base/telephony/java/android/telephony/SignalStrength.java)
-            response[7]  = -1;
-            response[8]  = -1;
-            response[9]  = -1;
-            response[10] = -1;
-            response[11] = -1;
+            response[7]  = -1; // lteSignalStrength
+            response[8]  = -1; // lteRsrp
+            response[9]  = -1; // lteRsrq
+            response[10] = -1; // lteRssnr
+            response[11] = -1; // lteCqi
+        } else if (mSignalbarCount) {
+            int num_bars = (response[7] & 0xff00) >> 8;
+            response[7] &= 0xff;        // remove the Samsung number of bars field
+            response[10] = INVALID_SNR; // mark lteRssnr invalid so it doesn't get used
+
+            // Translate number of bars into something SignalStrength.java can understand
+            switch (num_bars) {
+                case 0  : response[8] = -1;   break; // map to 0 bars
+                case 1  : response[8] = -116; break; // map to 1 bar
+                case 2  : response[8] = -115; break; // map to 2 bars
+                case 3  : response[8] = -105; break; // map to 3 bars
+                case 4  : response[8] = -95;  break; // map to 4 bars
+                case 5  : response[8] = -85;  break; // map to 4 bars but give an extra 10 dBm
+                default : response[8] *= -1;  break; // no idea; just pass value through
+            }
         } else {
+            response[7] &= 0xff;  // remove the Samsung number of bars field
             response[8] *= -1;
         }
 
+        Log.d(LOG_TAG, "responseSignalStength AFTER: mode=" + (mSignalbarCount ? "bars" : "raw") +
+            " gsmDbm=" + response[0] + " gsmEcio=" + response[1] +
+            " lteSignalStrength=" + response[7] + " lteRsrp=" + response[8] + " lteRsrq=" + response[9] +
+            " lteRssnr=" + response[10] + " lteCqi=" + response[11]);
         return response;
     }
 }