diff --git a/services/audioflinger/Threads.cpp b/services/audioflinger/Threads.cpp
index c8338b2..1f010b3 100644
--- a/services/audioflinger/Threads.cpp
+++ b/services/audioflinger/Threads.cpp
@@ -257,6 +257,61 @@
     return standbyTimeInNanos;
 }
 
+// Set kEnableExtendedChannels to true to enable greater than stereo output
+// for the MixerThread and device sink.  Number of channels allowed is
+// FCC_2 <= channels <= FCC_LIMIT.
+constexpr bool kEnableExtendedChannels = true;
+
+// Returns true if channel mask is permitted for the PCM sink in the MixerThread
+/* static */
+bool IAfThreadBase::isValidPcmSinkChannelMask(audio_channel_mask_t channelMask) {
+    switch (audio_channel_mask_get_representation(channelMask)) {
+    case AUDIO_CHANNEL_REPRESENTATION_POSITION: {
+        // Haptic channel mask is only applicable for channel position mask.
+        const uint32_t channelCount = audio_channel_count_from_out_mask(
+                static_cast<audio_channel_mask_t>(channelMask & ~AUDIO_CHANNEL_HAPTIC_ALL));
+        const uint32_t maxChannelCount = kEnableExtendedChannels
+                ? FCC_LIMIT : FCC_2;
+        if (channelCount < FCC_2 // mono is not supported at this time
+                || channelCount > maxChannelCount) {
+            return false;
+        }
+        // check that channelMask is the "canonical" one we expect for the channelCount.
+        return audio_channel_position_mask_is_out_canonical(channelMask);
+        }
+    case AUDIO_CHANNEL_REPRESENTATION_INDEX:
+        if (kEnableExtendedChannels) {
+            const uint32_t channelCount = audio_channel_count_from_out_mask(channelMask);
+            if (channelCount >= FCC_2 // mono is not supported at this time
+                    && channelCount <= FCC_LIMIT) {
+                return true;
+            }
+        }
+        return false;
+    default:
+        return false;
+    }
+}
+
+// Set kEnableExtendedPrecision to true to use extended precision in MixerThread
+constexpr bool kEnableExtendedPrecision = true;
+
+// Returns true if format is permitted for the PCM sink in the MixerThread
+/* static */
+bool IAfThreadBase::isValidPcmSinkFormat(audio_format_t format) {
+    switch (format) {
+    case AUDIO_FORMAT_PCM_16_BIT:
+        return true;
+    case AUDIO_FORMAT_PCM_FLOAT:
+    case AUDIO_FORMAT_PCM_24_BIT_PACKED:
+    case AUDIO_FORMAT_PCM_32_BIT:
+    case AUDIO_FORMAT_PCM_8_24_BIT:
+        return kEnableExtendedPrecision;
+    default:
+        return false;
+    }
+}
+
 // ----------------------------------------------------------------------------
 
 // TODO: move all toString helpers to audio.h
@@ -2077,12 +2132,12 @@
                                              audio_config_base_t *mixerConfig)
     :   ThreadBase(afThreadCallback, id, type, systemReady, true /* isOut */),
         mNormalFrameCount(0), mSinkBuffer(NULL),
-        mMixerBufferEnabled(AudioFlinger::kEnableExtendedPrecision || type == SPATIALIZER),
+        mMixerBufferEnabled(kEnableExtendedPrecision || type == SPATIALIZER),
         mMixerBuffer(NULL),
         mMixerBufferSize(0),
         mMixerBufferFormat(AUDIO_FORMAT_INVALID),
         mMixerBufferValid(false),
-        mEffectBufferEnabled(AudioFlinger::kEnableExtendedPrecision || type == SPATIALIZER),
+        mEffectBufferEnabled(kEnableExtendedPrecision || type == SPATIALIZER),
         mEffectBuffer(NULL),
         mEffectBufferSize(0),
         mEffectBufferFormat(AUDIO_FORMAT_INVALID),
@@ -3065,7 +3120,7 @@
     if (!audio_is_output_channel(mChannelMask)) {
         LOG_ALWAYS_FATAL("HAL channel mask %#x not valid for output", mChannelMask);
     }
-    if (hasMixer() && !AudioFlinger::isValidPcmSinkChannelMask(mChannelMask)) {
+    if (hasMixer() && !isValidPcmSinkChannelMask(mChannelMask)) {
         LOG_ALWAYS_FATAL("HAL channel mask %#x not supported for mixed output",
                 mChannelMask);
     }
@@ -3088,7 +3143,7 @@
     if (!audio_is_valid_format(mFormat)) {
         LOG_ALWAYS_FATAL("HAL format %#x not valid for output", mFormat);
     }
-    if (hasMixer() && !AudioFlinger::isValidPcmSinkFormat(mFormat)) {
+    if (hasMixer() && !isValidPcmSinkFormat(mFormat)) {
         LOG_FATAL("HAL format %#x not supported for mixed output",
                 mFormat);
     }
@@ -6217,7 +6272,7 @@
         reconfig = true;
     }
     if (param.getInt(String8(AudioParameter::keyFormat), value) == NO_ERROR) {
-        if (!AudioFlinger::isValidPcmSinkFormat(static_cast<audio_format_t>(value))) {
+        if (!isValidPcmSinkFormat(static_cast<audio_format_t>(value))) {
             status = BAD_VALUE;
         } else {
             // no need to save value, since it's constant
@@ -6225,7 +6280,7 @@
         }
     }
     if (param.getInt(String8(AudioParameter::keyChannels), value) == NO_ERROR) {
-        if (!AudioFlinger::isValidPcmSinkChannelMask(static_cast<audio_channel_mask_t>(value))) {
+        if (!isValidPcmSinkChannelMask(static_cast<audio_channel_mask_t>(value))) {
             status = BAD_VALUE;
         } else {
             // no need to save value, since it's constant