AudioFlinger: fix global effects suspend logic

Audio effects on the output mix should not be suspended when effects
on the output stage (post processing) are enabled.

Change-Id: I2e1c08fa9358ea3cbaec68856738d504b1be54e4
diff --git a/services/audioflinger/AudioFlinger.cpp b/services/audioflinger/AudioFlinger.cpp
index 56a9942..77b2bc8 100644
--- a/services/audioflinger/AudioFlinger.cpp
+++ b/services/audioflinger/AudioFlinger.cpp
@@ -1465,7 +1465,9 @@
         // suspend all effects in AUDIO_SESSION_OUTPUT_MIX when enabling any effect on
         // another session. This gives the priority to well behaved effect control panels
         // and applications not using global effects.
-        if (sessionId != AUDIO_SESSION_OUTPUT_MIX) {
+        // Enabling post processing in AUDIO_SESSION_OUTPUT_STAGE session does not affect
+        // global effects
+        if ((sessionId != AUDIO_SESSION_OUTPUT_MIX) && (sessionId != AUDIO_SESSION_OUTPUT_STAGE)) {
             setEffectSuspended_l(NULL, enabled, AUDIO_SESSION_OUTPUT_MIX);
         }
     }