diff --git a/services/audioflinger/Threads.cpp b/services/audioflinger/Threads.cpp
index ecbd0ae..90d3ef9 100644
--- a/services/audioflinger/Threads.cpp
+++ b/services/audioflinger/Threads.cpp
@@ -3220,9 +3220,9 @@
 
     // Calculate size of normal sink buffer relative to the HAL output buffer size
     double multiplier = 1.0;
-    // Note: mType == SPATIALIZER does not support FastMixer.
-    if (mType == MIXER && (kUseFastMixer == FastMixer_Static ||
-            kUseFastMixer == FastMixer_Dynamic)) {
+    // Note: mType == SPATIALIZER does not support FastMixer and DEEP is by definition not "fast"
+    if ((mType == MIXER && !(mOutput->flags & AUDIO_OUTPUT_FLAG_DEEP_BUFFER)) &&
+            (kUseFastMixer == FastMixer_Static || kUseFastMixer == FastMixer_Dynamic)) {
         size_t minNormalFrameCount = (kMinNormalSinkBufferSizeMs * mSampleRate) / 1000;
         size_t maxNormalFrameCount = (kMaxNormalSinkBufferSizeMs * mSampleRate) / 1000;
 
@@ -5135,7 +5135,16 @@
             break;
         case FastMixer_Static:
         case FastMixer_Dynamic:
-            initFastMixer = mFrameCount < mNormalFrameCount;
+            if (mType == MIXER && (output->flags & AUDIO_OUTPUT_FLAG_DEEP_BUFFER)) {
+                /* Do not init fast mixer on deep buffer, warn if buffers are confed too small */
+                initFastMixer = false;
+                ALOGW_IF(mFrameCount * 1000 / mSampleRate < kMinNormalSinkBufferSizeMs,
+                         "HAL DEEP BUFFER Buffer (%zu ms) is smaller than set minimal buffer "
+                         "(%u ms), seems like a configuration error",
+                         mFrameCount * 1000 / mSampleRate, kMinNormalSinkBufferSizeMs);
+            } else {
+                initFastMixer = mFrameCount < mNormalFrameCount;
+            }
             break;
         }
         ALOGW_IF(initFastMixer == false && mFrameCount < mNormalFrameCount,