Apparently a MemoryHeapPMem must be slap()ed for SurfaceFlinger to use the contained buffers.

        LOGI("Creating physical memory heap failed, reverting to regular heap.");

        mMemoryHeap = new MemoryHeapBase(2 * mFrameSize);

    } else {

        mMemoryHeap = new MemoryHeapPmem(mMemoryHeap);

        sp<MemoryHeapPmem> pmemHeap = new MemoryHeapPmem(mMemoryHeap);

        pmemHeap->slap();

        mMemoryHeap = pmemHeap;

    }

    CHECK(mISurface.get() != NULL);