enable ALLOW_DEQUEUE_CURRENT_BUFFER for tegra devices

this flag should be enabled for all targets, but currently
some have issues with it, so we're turning it on only for
tested targets.

this will hopefully resolve some performance issues.

Bug: 5553562
Change-Id: I939992b4cd0debea980dec0127c72be2dff33af8

Author: pixelflinger

libs/gui/Android.mk

@@ -32,6 +32,10 @@ LOCAL_SHARED_LIBRARIES := \
 
 LOCAL_MODULE:= libgui
 
+ifeq ($(TARGET_BOARD_PLATFORM), tegra)
+	LOCAL_CFLAGS += -DALLOW_DEQUEUE_CURRENT_BUFFER
+endif
+
 include $(BUILD_SHARED_LIBRARY)
 
 ifeq (,$(ONE_SHOT_MAKEFILE))

libs/gui/SurfaceTexture.cpp

@@ -36,8 +36,12 @@
 #include <utils/Log.h>
 #include <utils/String8.h>
 
-
-#define ALLOW_DEQUEUE_CURRENT_BUFFER    false
+#ifdef ALLOW_DEQUEUE_CURRENT_BUFFER
+#define FLAG_ALLOW_DEQUEUE_CURRENT_BUFFER    true
+#warning "ALLOW_DEQUEUE_CURRENT_BUFFER enabled"
+#else
+#define FLAG_ALLOW_DEQUEUE_CURRENT_BUFFER    false
+#endif
 
 // Macros for including the SurfaceTexture name in log messages
 #define ST_LOGV(x, ...) LOGV("[%s] "x, mName.string(), ##__VA_ARGS__)
@@ -323,7 +327,7 @@ status_t SurfaceTexture::dequeueBuffer(int *outBuf, uint32_t w, uint32_t h,
             LOGW_IF((state == BufferSlot::FREE) && (mCurrentTexture==i),
                     "dequeueBuffer: buffer %d is both FREE and current!", i);
 
-            if (ALLOW_DEQUEUE_CURRENT_BUFFER) {
+            if (FLAG_ALLOW_DEQUEUE_CURRENT_BUFFER) {
                 if (state == BufferSlot::FREE || i == mCurrentTexture) {
                     foundSync = i;
                     if (i != mCurrentTexture) {