Refine broadcastradio HAL comments.

Bug: b/64113304
Test: it builds
Change-Id: I42c1d32dbe436c97f0a05b4fdb88f60f11ceb0a1

broadcastradio/1.0/types.hal

@@ -212,12 +212,23 @@ struct ProgramInfo {
     uint32_t     channel;   /** current channel. (e.g kHz for band type AM_FM) */
     uint32_t     subChannel; /** current sub channel. (FM_HD) */
 
-    /** Tuned to a program (not a noise). It's the same condition that would stop scan operation. */
+    /**
+     * Tuned to a program (not a noise). It's the same condition that would
+     * stop scan operation.
+     */
     bool         tuned;
 
     bool         stereo;    /** program is stereo or not */
     bool         digital;   /** digital program or not (e.g HD Radio program) */
-    uint32_t     signalStrength; /** signal strength from 0 to 100 */
-    vec<MetaData> metadata; /** non empty if meta data are present (e.g PTY, song title ...) */
+
+    /**
+     * Signal quality measured in 0% to 100% range.
+     *
+     * Despite the name, this is not a signal strength.
+     * The purpose of this field is primarily informative.
+     */
+    uint32_t signalStrength;
+
+    vec<MetaData> metadata; /** Metadata: PTY, song title etc. */
 };
 

broadcastradio/1.1/ITuner.hal

@@ -84,6 +84,13 @@ interface ITuner extends @1.0::ITuner {
      * subsequent calls to startBackgroundScan, issuing a single
      * backgroundScanComplete callback.
      *
+     * If a device supports continuous background scanning, it may succeed
+     * (return OK and call backgroundScanComplete) without any additional
+     * operation performed.
+     *
+     * Foreground scanning may be implemented in the front end app with
+     * @1.0::ITuner scan operation.
+     *
      * @return result OK if the scan was properly scheduled (this does not mean
      *                it successfully finished).
      *                UNAVAILABLE if the background scan is unavailable,

current.txt

@@ -190,6 +190,7 @@ fe3c3c2f572b72f15f8594c538b0577bd5c28722c31879cfe6231330cddb6747 android.hardwar
 # ABI preserving changes to HALs released in Android O
 
 150a338ce11fcec70757c9675d83cf6a5d7b40d0c812741b91671fecce59eac9 android.hardware.broadcastradio@1.0::types
+dc7e6d4f537b9943e27edc4f86c5a03bb643b18f18f866f8c3c71c0ac4ea8cbc android.hardware.broadcastradio@1.0::types
 760485232f6cce07f8bb05e3475509956996b702f77415ee5bff05e2ec5a5bcc android.hardware.dumpstate@1.0::IDumpstateDevice
 e822cb7f4a1bdd45689c5e92ccd19a2201c20b771bd4b2ec1ae627e324591f9d android.hardware.radio@1.0::IRadioResponse
 28e929b453df3d9f5060af2764e6cdb123ddb893e3e86923c877f6ff7e5f02c9 android.hardware.wifi@1.0::types