Fix effect and mono sink handling.

Do not permit mixing to mono sink in AudioFlinger.
Allow effects on mono sink if not Mixer thread (e.g. Record).

Bug: 16863095
Change-Id: I8b232fc1fb3f07bf017020c5d4f9ace644dec6d8
diff --git a/services/audioflinger/Threads.cpp b/services/audioflinger/Threads.cpp
index 2f65370..7d583bb5 100644
--- a/services/audioflinger/Threads.cpp
+++ b/services/audioflinger/Threads.cpp
@@ -910,11 +910,11 @@
         goto Exit;
     }
 
-    // Reject any effect on multichannel sinks.
+    // Reject any effect on mixer or duplicating multichannel sinks.
     // TODO: fix both format and multichannel issues with effects.
-    if (mChannelCount != FCC_2) {
-        ALOGW("createEffect_l() Cannot add effect %s for multichannel(%d) thread",
-                desc->name, mChannelCount);
+    if ((mType == MIXER || mType == DUPLICATING) && mChannelCount != FCC_2) {
+        ALOGW("createEffect_l() Cannot add effect %s for multichannel(%d) %s threads",
+                desc->name, mChannelCount, mType == MIXER ? "MIXER" : "DUPLICATING");
         lStatus = BAD_VALUE;
         goto Exit;
     }