commit 9abe1ebc9575dc5a19bf1dfce6e9b02e03374457
author Daniel Lam <dalam@google.com> Mon Mar 26 20:37:15 2012 -0700
committer Daniel Lam <dalam@google.com> Mon Apr 02 14:55:01 2012 -0700
tree c363e3977311b0bc9d929cf9103e2bb3101e76d3
parent 0e1080f887bcd80c75910cabe7b2eca224bf739c

Fixed disconnect bug in SurfaceTexture

BufferQueue's disconnect could race with updateTexImage
where invalid buffers could be released.  Additionally
fixed similar bug with setBufferCount.  Tests were added
to stress the disconnect mechanism.

Change-Id: I9afa4c64f3e025984e8a9e8d924852a71d044716

libs/gui/SurfaceTexture.cpp

diff --git a/libs/gui/SurfaceTexture.cpp b/libs/gui/SurfaceTexture.cpp
index 18c86fa..dd96f84 100644
--- a/libs/gui/SurfaceTexture.cpp
+++ b/libs/gui/SurfaceTexture.cpp
@@ -176,6 +176,8 @@
     ST_LOGV("updateTexImage");
     Mutex::Autolock lock(mMutex);
 
+    status_t err = NO_ERROR;
+
     if (mAbandoned) {
         ST_LOGE("updateTexImage: SurfaceTexture is abandoned!");
         return NO_INIT;
@@ -269,11 +271,17 @@
                 mCurrentTextureBuf != NULL ? mCurrentTextureBuf->handle : 0,
                 buf, item.mGraphicBuffer != NULL ? item.mGraphicBuffer->handle : 0);
 
-        // Release the old buffer
+        // release old buffer
         if (mCurrentTexture != BufferQueue::INVALID_BUFFER_SLOT) {
-            mBufferQueue->releaseBuffer(mCurrentTexture, dpy,
-                    mEGLSlots[mCurrentTexture].mFence);
+            status_t status = mBufferQueue->releaseBuffer(mCurrentTexture, dpy, mEGLSlots[mCurrentTexture].mFence);
+
             mEGLSlots[mCurrentTexture].mFence = EGL_NO_SYNC_KHR;
+            if (status == BufferQueue::STALE_BUFFER_SLOT) {
+                freeBufferLocked(mCurrentTexture);
+            } else if (status != OK) {
+                ST_LOGE("updateTexImage: released invalid buffer");
+                err = status;
+            }
         }
 
         // Update the SurfaceTexture state.
@@ -289,7 +297,7 @@
         glBindTexture(mTexTarget, mTexName);
     }
 
-    return OK;
+    return err;
 }
 
 status_t SurfaceTexture::detachFromContext() {
@@ -630,6 +638,9 @@
 void SurfaceTexture::freeBufferLocked(int slotIndex) {
     ST_LOGV("freeBufferLocked: slotIndex=%d", slotIndex);
     mEGLSlots[slotIndex].mGraphicBuffer = 0;
+    if (slotIndex == mCurrentTexture) {
+        mCurrentTexture = BufferQueue::INVALID_BUFFER_SLOT;
+    }
     if (mEGLSlots[slotIndex].mEglImage != EGL_NO_IMAGE_KHR) {
         EGLImageKHR img = mEGLSlots[slotIndex].mEglImage;
         if (img != EGL_NO_IMAGE_KHR) {
@@ -693,12 +704,6 @@
 }
 
 // Used for refactoring, should not be in final interface
-status_t SurfaceTexture::setBufferCount(int bufferCount) {
-    Mutex::Autolock lock(mMutex);
-    return mBufferQueue->setBufferCount(bufferCount);
-}
-
-// Used for refactoring, should not be in final interface
 status_t SurfaceTexture::connect(int api,
                 uint32_t* outWidth, uint32_t* outHeight, uint32_t* outTransform) {
     Mutex::Autolock lock(mMutex);
@@ -737,8 +742,6 @@
             freeBufferLocked(i);
         }
     }
-
-    mCurrentTexture = BufferQueue::INVALID_BUFFER_SLOT;
 }
 
 void SurfaceTexture::dump(String8& result) const