diff --git a/libs/vr/libbufferhubqueue/buffer_hub_queue_client.cpp b/libs/vr/libbufferhubqueue/buffer_hub_queue_client.cpp
index 012a4e7..1978f41 100644
--- a/libs/vr/libbufferhubqueue/buffer_hub_queue_client.cpp
+++ b/libs/vr/libbufferhubqueue/buffer_hub_queue_client.cpp
@@ -23,34 +23,61 @@
 
 using android::pdx::ErrorStatus;
 using android::pdx::LocalChannelHandle;
+using android::pdx::LocalHandle;
 using android::pdx::Status;
 
 namespace android {
 namespace dvr {
 
+namespace {
+
+// Polls an fd for the given events.
+Status<int> PollEvents(int fd, short events) {
+  const int kTimeoutMs = 0;
+  pollfd pfd{fd, events, 0};
+  const int count = RETRY_EINTR(poll(&pfd, 1, kTimeoutMs));
+  if (count < 0) {
+    return ErrorStatus(errno);
+  } else if (count == 0) {
+    return ErrorStatus(ETIMEDOUT);
+  } else {
+    return {pfd.revents};
+  }
+}
+
+// Polls a buffer for the given events, taking care to do the proper
+// translation.
+Status<int> PollEvents(const std::shared_ptr<BufferHubBuffer>& buffer,
+                       short events) {
+  auto poll_status = PollEvents(buffer->event_fd(), events);
+  if (!poll_status)
+    return poll_status;
+
+  return buffer->GetEventMask(poll_status.get());
+}
+
+std::pair<int32_t, int32_t> Unstuff(uint64_t value) {
+  return {static_cast<int32_t>(value >> 32),
+          static_cast<int32_t>(value & ((1ull << 32) - 1))};
+}
+
+uint64_t Stuff(int32_t a, int32_t b) {
+  const uint32_t ua = static_cast<uint32_t>(a);
+  const uint32_t ub = static_cast<uint32_t>(b);
+  return (static_cast<uint64_t>(ua) << 32) | static_cast<uint64_t>(ub);
+}
+
+}  // anonymous namespace
+
 BufferHubQueue::BufferHubQueue(LocalChannelHandle channel_handle)
     : Client{pdx::default_transport::ClientChannel::Create(
-          std::move(channel_handle))},
-      meta_size_(0),
-      buffers_(BufferHubQueue::kMaxQueueCapacity),
-      epollhup_pending_(BufferHubQueue::kMaxQueueCapacity, false),
-      available_buffers_(BufferHubQueue::kMaxQueueCapacity),
-      fences_(BufferHubQueue::kMaxQueueCapacity),
-      capacity_(0),
-      id_(-1) {
+          std::move(channel_handle))} {
   Initialize();
 }
 
 BufferHubQueue::BufferHubQueue(const std::string& endpoint_path)
-    : Client{pdx::default_transport::ClientChannelFactory::Create(
-          endpoint_path)},
-      meta_size_(0),
-      buffers_(BufferHubQueue::kMaxQueueCapacity),
-      epollhup_pending_(BufferHubQueue::kMaxQueueCapacity, false),
-      available_buffers_(BufferHubQueue::kMaxQueueCapacity),
-      fences_(BufferHubQueue::kMaxQueueCapacity),
-      capacity_(0),
-      id_(-1) {
+    : Client{
+          pdx::default_transport::ClientChannelFactory::Create(endpoint_path)} {
   Initialize();
 }
 
@@ -62,9 +89,9 @@
     return;
   }
 
-  epoll_event event = {.events = EPOLLIN | EPOLLET,
-                       .data = {.u64 = static_cast<uint64_t>(
-                                    BufferHubQueue::kEpollQueueEventIndex)}};
+  epoll_event event = {
+      .events = EPOLLIN | EPOLLET,
+      .data = {.u64 = Stuff(-1, BufferHubQueue::kEpollQueueEventIndex)}};
   ret = epoll_fd_.Control(EPOLL_CTL_ADD, event_fd(), &event);
   if (ret < 0) {
     ALOGE("BufferHubQueue::Initialize: Failed to add event fd to epoll set: %s",
@@ -87,7 +114,6 @@
 void BufferHubQueue::SetupQueue(size_t meta_size_bytes, int id) {
   meta_size_ = meta_size_bytes;
   id_ = id;
-  meta_buffer_tmp_.reset(meta_size_ > 0 ? new uint8_t[meta_size_] : nullptr);
 }
 
 std::unique_ptr<ConsumerQueue> BufferHubQueue::CreateConsumerQueue() {
@@ -152,19 +178,24 @@
     // one for each buffer, in the queue and one extra event for the queue
     // client itself.
     for (int i = 0; i < num_events; i++) {
-      int64_t index = static_cast<int64_t>(events[i].data.u64);
+      int32_t event_fd;
+      int32_t index;
+      std::tie(event_fd, index) = Unstuff(events[i].data.u64);
 
       ALOGD_IF(TRACE,
-               "BufferHubQueue::WaitForBuffers: event %d: index=%" PRId64, i,
-               index);
+               "BufferHubQueue::WaitForBuffers: event %d: event_fd=%d index=%d",
+               i, event_fd, index);
 
       if (is_buffer_event_index(index)) {
-        HandleBufferEvent(static_cast<size_t>(index), events[i].events);
+        HandleBufferEvent(static_cast<size_t>(index), event_fd,
+                          events[i].events);
       } else if (is_queue_event_index(index)) {
         HandleQueueEvent(events[i].events);
       } else {
-        ALOGW("BufferHubQueue::WaitForBuffers: Unknown event index: %" PRId64,
-              index);
+        ALOGW(
+            "BufferHubQueue::WaitForBuffers: Unknown event type event_fd=%d "
+            "index=%d",
+            event_fd, index);
       }
     }
   } while (count() == 0 && capacity() > 0 && !hung_up());
@@ -172,52 +203,72 @@
   return count() != 0;
 }
 
-void BufferHubQueue::HandleBufferEvent(size_t slot, int poll_events) {
-  auto buffer = buffers_[slot];
-  if (!buffer) {
+Status<void> BufferHubQueue::HandleBufferEvent(size_t slot, int event_fd,
+                                               int poll_events) {
+  if (!buffers_[slot]) {
     ALOGW("BufferHubQueue::HandleBufferEvent: Invalid buffer slot: %zu", slot);
-    return;
+    return ErrorStatus(ENOENT);
   }
 
-  auto status = buffer->GetEventMask(poll_events);
+  auto status = buffers_[slot]->GetEventMask(poll_events);
   if (!status) {
     ALOGW("BufferHubQueue::HandleBufferEvent: Failed to get event mask: %s",
           status.GetErrorMessage().c_str());
-    return;
+    return status.error_status();
   }
 
   const int events = status.get();
   if (events & EPOLLIN) {
-    const int ret = OnBufferReady(buffer, &fences_[slot]);
-    if (ret == 0 || ret == -EALREADY || ret == -EBUSY) {
+    auto entry_status = OnBufferReady(buffers_[slot], slot);
+    if (entry_status.ok() || entry_status.error() == EALREADY) {
       // Only enqueue the buffer if it moves to or is already in the state
-      // requested in OnBufferReady(). If the buffer is busy this means that the
-      // buffer moved from released to posted when a new consumer was created
-      // before the ProducerQueue had a chance to regain it. This is a valid
-      // transition that we have to handle because edge triggered poll events
-      // latch the ready state even if it is later de-asserted -- don't enqueue
-      // or print an error log in this case.
-      if (ret != -EBUSY)
-        Enqueue(buffer, slot);
+      // requested in OnBufferReady().
+      return Enqueue(entry_status.take());
+    } else if (entry_status.error() == EBUSY) {
+      // If the buffer is busy this means that the buffer moved from released to
+      // posted when a new consumer was created before the ProducerQueue had a
+      // chance to regain it. This is a valid transition that we have to handle
+      // because edge triggered poll events latch the ready state even if it is
+      // later de-asserted -- don't enqueue or print an error log in this case.
     } else {
       ALOGE(
           "BufferHubQueue::HandleBufferEvent: Failed to set buffer ready, "
           "queue_id=%d buffer_id=%d: %s",
-          id(), buffer->id(), strerror(-ret));
+          id(), buffers_[slot]->id(), entry_status.GetErrorMessage().c_str());
     }
   } else if (events & EPOLLHUP) {
-    // This might be caused by producer replacing an existing buffer slot, or
-    // when BufferHubQueue is shutting down. For the first case, currently the
-    // epoll FD is cleaned up when the replacement consumer client is imported,
-    // we shouldn't detach again if |epollhub_pending_[slot]| is set.
+    // Check to see if the current buffer in the slot hung up. This is a bit of
+    // paranoia to deal with the epoll set getting out of sync with the buffer
+    // slots.
+    auto poll_status = PollEvents(buffers_[slot], POLLIN);
+    if (!poll_status && poll_status.error() != ETIMEDOUT) {
+      ALOGE("BufferHubQueue::HandleBufferEvent: Failed to poll buffer: %s",
+            poll_status.GetErrorMessage().c_str());
+      return poll_status.error_status();
+    }
+
+    const bool hangup_pending = status.ok() && (poll_status.get() & EPOLLHUP);
+
     ALOGW(
-        "BufferHubQueue::HandleBufferEvent: Received EPOLLHUP at slot: %zu, "
-        "buffer event fd: %d, EPOLLHUP pending: %d",
-        slot, buffer->event_fd(), int{epollhup_pending_[slot]});
-    if (epollhup_pending_[slot]) {
-      epollhup_pending_[slot] = false;
+        "BufferHubQueue::HandleBufferEvent: Received EPOLLHUP event: slot=%zu "
+        "event_fd=%d buffer_id=%d hangup_pending=%d poll_status=%x",
+        slot, buffers_[slot]->event_fd(), buffers_[slot]->id(), hangup_pending,
+        poll_status.get());
+
+    if (hangup_pending) {
+      return DetachBuffer(slot);
     } else {
-      DetachBuffer(slot);
+      // Clean up the bookkeeping for the event fd. This is a bit of paranoia to
+      // deal with the epoll set getting out of sync with the buffer slots.
+      // Hitting this path should be very unusual.
+      const int ret = epoll_fd_.Control(EPOLL_CTL_DEL, event_fd, nullptr);
+      if (ret < 0) {
+        ALOGE(
+            "BufferHubQueue::HandleBufferEvent: Failed to remove fd=%d from "
+            "epoll set: %s",
+            event_fd, strerror(-ret));
+        return ErrorStatus(-ret);
+      }
     }
   } else {
     ALOGW(
@@ -225,14 +276,16 @@
         "events=%d",
         slot, events);
   }
+
+  return {};
 }
 
-void BufferHubQueue::HandleQueueEvent(int poll_event) {
+Status<void> BufferHubQueue::HandleQueueEvent(int poll_event) {
   auto status = GetEventMask(poll_event);
   if (!status) {
     ALOGW("BufferHubQueue::HandleQueueEvent: Failed to get event mask: %s",
           status.GetErrorMessage().c_str());
-    return;
+    return status.error_status();
   }
 
   const int events = status.get();
@@ -250,111 +303,97 @@
   } else {
     ALOGW("BufferHubQueue::HandleQueueEvent: Unknown epoll events=%x", events);
   }
+
+  return {};
 }
 
-int BufferHubQueue::AddBuffer(const std::shared_ptr<BufferHubBuffer>& buf,
-                              size_t slot) {
+Status<void> BufferHubQueue::AddBuffer(
+    const std::shared_ptr<BufferHubBuffer>& buffer, size_t slot) {
+  ALOGD_IF(TRACE, "BufferHubQueue::AddBuffer: buffer_id=%d slot=%zu",
+           buffer->id(), slot);
+
   if (is_full()) {
-    // TODO(jwcai) Move the check into Producer's AllocateBuffer and consumer's
-    // import buffer.
     ALOGE("BufferHubQueue::AddBuffer queue is at maximum capacity: %zu",
           capacity_);
-    return -E2BIG;
+    return ErrorStatus(E2BIG);
   }
 
-  if (buffers_[slot] != nullptr) {
-    // Replace the buffer if the slot is preoccupied. This could happen when the
+  if (buffers_[slot]) {
+    // Replace the buffer if the slot is occupied. This could happen when the
     // producer side replaced the slot with a newly allocated buffer. Detach the
     // buffer before setting up with the new one.
-    DetachBuffer(slot);
-    epollhup_pending_[slot] = true;
+    auto detach_status = DetachBuffer(slot);
+    if (!detach_status)
+      return detach_status.error_status();
   }
 
-  epoll_event event = {.events = EPOLLIN | EPOLLET, .data = {.u64 = slot}};
-  const int ret = epoll_fd_.Control(EPOLL_CTL_ADD, buf->event_fd(), &event);
+  epoll_event event = {.events = EPOLLIN | EPOLLET,
+                       .data = {.u64 = Stuff(buffer->event_fd(), slot)}};
+  const int ret = epoll_fd_.Control(EPOLL_CTL_ADD, buffer->event_fd(), &event);
   if (ret < 0) {
     ALOGE("BufferHubQueue::AddBuffer: Failed to add buffer to epoll set: %s",
           strerror(-ret));
-    return ret;
+    return ErrorStatus(-ret);
   }
 
-  buffers_[slot] = buf;
+  buffers_[slot] = buffer;
   capacity_++;
-  return 0;
+  return {};
 }
 
-int BufferHubQueue::DetachBuffer(size_t slot) {
-  auto& buf = buffers_[slot];
-  if (buf == nullptr) {
-    ALOGE("BufferHubQueue::DetachBuffer: Invalid slot: %zu", slot);
-    return -EINVAL;
+Status<void> BufferHubQueue::DetachBuffer(size_t slot) {
+  ALOGD_IF(TRACE, "BufferHubQueue::DetachBuffer: slot=%zu", slot);
+
+  if (buffers_[slot]) {
+    const int ret =
+        epoll_fd_.Control(EPOLL_CTL_DEL, buffers_[slot]->event_fd(), nullptr);
+    if (ret < 0) {
+      ALOGE(
+          "BufferHubQueue::DetachBuffer: Failed to detach buffer from epoll "
+          "set: "
+          "%s",
+          strerror(-ret));
+      return ErrorStatus(-ret);
+    }
+
+    buffers_[slot] = nullptr;
+    capacity_--;
   }
 
-  const int ret = epoll_fd_.Control(EPOLL_CTL_DEL, buf->event_fd(), nullptr);
-  if (ret < 0) {
-    ALOGE(
-        "BufferHubQueue::DetachBuffer: Failed to detach buffer from epoll set: "
-        "%s",
-        strerror(-ret));
-    return ret;
-  }
-
-  buffers_[slot] = nullptr;
-  capacity_--;
-  return 0;
+  return {};
 }
 
-void BufferHubQueue::Enqueue(const std::shared_ptr<BufferHubBuffer>& buf,
-                             size_t slot) {
-  if (count() == capacity_) {
+Status<void> BufferHubQueue::Enqueue(Entry entry) {
+  if (!is_full()) {
+    available_buffers_.Append(std::move(entry));
+    return {};
+  } else {
     ALOGE("BufferHubQueue::Enqueue: Buffer queue is full!");
-    return;
+    return ErrorStatus(E2BIG);
   }
-
-  // Set slot buffer back to vector.
-  // TODO(jwcai) Here have to dynamically allocate BufferInfo::metadata due to
-  // the limitation of the RingBuffer we are using. Would be better to refactor
-  // that.
-  BufferInfo buffer_info(slot, meta_size_);
-  buffer_info.buffer = buf;
-  // Swap metadata loaded during onBufferReady into vector.
-  std::swap(buffer_info.metadata, meta_buffer_tmp_);
-
-  available_buffers_.Append(std::move(buffer_info));
 }
 
 Status<std::shared_ptr<BufferHubBuffer>> BufferHubQueue::Dequeue(
     int timeout, size_t* slot, void* meta, LocalHandle* fence) {
-  ALOGD_IF(TRACE, "Dequeue: count=%zu, timeout=%d", count(), timeout);
+  ALOGD_IF(TRACE, "BufferHubQueue::Dequeue: count=%zu, timeout=%d", count(),
+           timeout);
 
   if (!WaitForBuffers(timeout))
     return ErrorStatus(ETIMEDOUT);
 
-  std::shared_ptr<BufferHubBuffer> buf;
-  BufferInfo& buffer_info = available_buffers_.Front();
+  auto& entry = available_buffers_.Front();
 
-  *fence = std::move(fences_[buffer_info.slot]);
-
-  // Report current pos as the output slot.
-  std::swap(buffer_info.slot, *slot);
-  // Swap buffer from vector to be returned later.
-  std::swap(buffer_info.buffer, buf);
-  // Swap metadata from vector into tmp so that we can write out to |meta|.
-  std::swap(buffer_info.metadata, meta_buffer_tmp_);
-
-  available_buffers_.PopFront();
-
-  if (!buf) {
-    ALOGE("BufferHubQueue::Dequeue: Buffer to be dequeued is nullptr");
-    return ErrorStatus(ENOBUFS);
-  }
-
-  if (meta) {
-    std::copy(meta_buffer_tmp_.get(), meta_buffer_tmp_.get() + meta_size_,
+  std::shared_ptr<BufferHubBuffer> buffer = std::move(entry.buffer);
+  *slot = entry.slot;
+  *fence = std::move(entry.fence);
+  if (meta && entry.metadata) {
+    std::copy(entry.metadata.get(), entry.metadata.get() + meta_size_,
               reinterpret_cast<uint8_t*>(meta));
   }
 
-  return {std::move(buf)};
+  available_buffers_.PopFront();
+
+  return {std::move(buffer)};
 }
 
 ProducerQueue::ProducerQueue(size_t meta_size)
@@ -388,28 +427,29 @@
   SetupQueue(status.get().meta_size_bytes, status.get().id);
 }
 
-int ProducerQueue::AllocateBuffer(uint32_t width, uint32_t height,
-                                  uint32_t layer_count, uint32_t format,
-                                  uint64_t usage, size_t* out_slot) {
+Status<void> ProducerQueue::AllocateBuffer(uint32_t width, uint32_t height,
+                                           uint32_t layer_count,
+                                           uint32_t format, uint64_t usage,
+                                           size_t* out_slot) {
   if (out_slot == nullptr) {
     ALOGE("ProducerQueue::AllocateBuffer: Parameter out_slot cannot be null.");
-    return -EINVAL;
+    return ErrorStatus(EINVAL);
   }
 
   if (is_full()) {
     ALOGE("ProducerQueue::AllocateBuffer queue is at maximum capacity: %zu",
           capacity());
-    return -E2BIG;
+    return ErrorStatus(E2BIG);
   }
 
-  const size_t kBufferCount = 1U;
+  const size_t kBufferCount = 1u;
   Status<std::vector<std::pair<LocalChannelHandle, size_t>>> status =
       InvokeRemoteMethod<BufferHubRPC::ProducerQueueAllocateBuffers>(
           width, height, layer_count, format, usage, kBufferCount);
   if (!status) {
     ALOGE("ProducerQueue::AllocateBuffer failed to create producer buffer: %s",
           status.GetErrorMessage().c_str());
-    return -status.error();
+    return status.error_status();
   }
 
   auto buffer_handle_slots = status.take();
@@ -429,27 +469,26 @@
                    buffer_slot);
 }
 
-int ProducerQueue::AddBuffer(const std::shared_ptr<BufferProducer>& buf,
-                             size_t slot) {
+Status<void> ProducerQueue::AddBuffer(
+    const std::shared_ptr<BufferProducer>& buffer, size_t slot) {
   ALOGD_IF(TRACE, "ProducerQueue::AddBuffer: queue_id=%d buffer_id=%d slot=%zu",
-           id(), buf->id(), slot);
+           id(), buffer->id(), slot);
   // For producer buffer, we need to enqueue the newly added buffer
   // immediately. Producer queue starts with all buffers in available state.
-  const int ret = BufferHubQueue::AddBuffer(buf, slot);
-  if (ret < 0)
-    return ret;
+  auto status = BufferHubQueue::AddBuffer(buffer, slot);
+  if (!status)
+    return status;
 
-  Enqueue(buf, slot);
-  return 0;
+  return Enqueue(buffer, slot);
 }
 
-int ProducerQueue::DetachBuffer(size_t slot) {
+Status<void> ProducerQueue::DetachBuffer(size_t slot) {
   auto status =
       InvokeRemoteMethod<BufferHubRPC::ProducerQueueDetachBuffer>(slot);
   if (!status) {
     ALOGE("ProducerQueue::DetachBuffer: Failed to detach producer buffer: %s",
           status.GetErrorMessage().c_str());
-    return -status.error();
+    return status.error_status();
   }
 
   return BufferHubQueue::DetachBuffer(slot);
@@ -471,12 +510,22 @@
   return {std::static_pointer_cast<BufferProducer>(buffer_status.take())};
 }
 
-int ProducerQueue::OnBufferReady(const std::shared_ptr<BufferHubBuffer>& buf,
-                                 LocalHandle* release_fence) {
-  ALOGD_IF(TRACE, "ProducerQueue::OnBufferReady: queue_id=%d buffer_id=%d",
-           id(), buf->id());
-  auto buffer = std::static_pointer_cast<BufferProducer>(buf);
-  return buffer->Gain(release_fence);
+Status<BufferHubQueue::Entry> ProducerQueue::OnBufferReady(
+    const std::shared_ptr<BufferHubBuffer>& buffer, size_t slot) {
+  ALOGD_IF(TRACE,
+           "ProducerQueue::OnBufferReady: queue_id=%d buffer_id=%d slot=%zu",
+           id(), buffer->id(), slot);
+
+  // Avoid taking a transient reference, buffer is valid for the duration of
+  // this method call.
+  auto* producer_buffer = static_cast<BufferProducer*>(buffer.get());
+  LocalHandle release_fence;
+
+  const int ret = producer_buffer->Gain(&release_fence);
+  if (ret < 0)
+    return ErrorStatus(-ret);
+  else
+    return {{buffer, nullptr, std::move(release_fence), slot}};
 }
 
 ConsumerQueue::ConsumerQueue(LocalChannelHandle handle, bool ignore_on_import)
@@ -503,12 +552,12 @@
   if (!status) {
     ALOGE("ConsumerQueue::ImportBuffers: Failed to import consumer buffer: %s",
           status.GetErrorMessage().c_str());
-    return ErrorStatus(status.error());
+    return status.error_status();
   }
 
   int ret;
-  int last_error = 0;
-  int imported_buffers = 0;
+  Status<void> last_error;
+  size_t imported_buffers_count = 0;
 
   auto buffer_handle_slots = status.take();
   for (auto& buffer_handle_slot : buffer_handle_slots) {
@@ -530,53 +579,52 @@
             "ConsumerQueue::ImportBuffers: Failed to set ignored state on "
             "imported buffer buffer_id=%d: %s",
             buffer_consumer->id(), strerror(-ret));
-        last_error = ret;
+        last_error = ErrorStatus(-ret);
       }
     }
 
-    ret = AddBuffer(std::move(buffer_consumer), buffer_handle_slot.second);
-    if (ret < 0) {
+    auto add_status =
+        AddBuffer(std::move(buffer_consumer), buffer_handle_slot.second);
+    if (!add_status) {
       ALOGE("ConsumerQueue::ImportBuffers: Failed to add buffer: %s",
-            strerror(-ret));
-      last_error = ret;
-      continue;
+            add_status.GetErrorMessage().c_str());
+      last_error = add_status;
     } else {
-      imported_buffers++;
+      imported_buffers_count++;
     }
   }
 
-  if (imported_buffers > 0)
-    return {imported_buffers};
+  if (imported_buffers_count > 0)
+    return {imported_buffers_count};
   else
-    return ErrorStatus(-last_error);
+    return last_error.error_status();
 }
 
-int ConsumerQueue::AddBuffer(const std::shared_ptr<BufferConsumer>& buf,
-                             size_t slot) {
+Status<void> ConsumerQueue::AddBuffer(
+    const std::shared_ptr<BufferConsumer>& buffer, size_t slot) {
   ALOGD_IF(TRACE, "ConsumerQueue::AddBuffer: queue_id=%d buffer_id=%d slot=%zu",
-           id(), buf->id(), slot);
-  const int ret = BufferHubQueue::AddBuffer(buf, slot);
-  if (ret < 0)
-    return ret;
+           id(), buffer->id(), slot);
+  auto status = BufferHubQueue::AddBuffer(buffer, slot);
+  if (!status)
+    return status;
 
   // Check to see if the buffer is already signaled. This is necessary to catch
   // cases where buffers are already available; epoll edge triggered mode does
   // not fire until and edge transition when adding new buffers to the epoll
-  // set.
-  const int kTimeoutMs = 0;
-  pollfd pfd{buf->event_fd(), POLLIN, 0};
-  const int count = RETRY_EINTR(poll(&pfd, 1, kTimeoutMs));
-  if (count < 0) {
-    const int error = errno;
+  // set. Note that we only poll the fd events because HandleBufferEvent() takes
+  // care of checking the translated buffer events.
+  auto poll_status = PollEvents(buffer->event_fd(), POLLIN);
+  if (!poll_status && poll_status.error() != ETIMEDOUT) {
     ALOGE("ConsumerQueue::AddBuffer: Failed to poll consumer buffer: %s",
-          strerror(errno));
-    return -error;
+          poll_status.GetErrorMessage().c_str());
+    return poll_status.error_status();
   }
 
-  if (count == 1)
-    HandleBufferEvent(slot, pfd.revents);
-
-  return 0;
+  // Update accounting if the buffer is available.
+  if (poll_status)
+    return HandleBufferEvent(slot, buffer->event_fd(), poll_status.get());
+  else
+    return {};
 }
 
 Status<std::shared_ptr<BufferConsumer>> ConsumerQueue::Dequeue(
@@ -606,15 +654,30 @@
   return {std::static_pointer_cast<BufferConsumer>(buffer_status.take())};
 }
 
-int ConsumerQueue::OnBufferReady(const std::shared_ptr<BufferHubBuffer>& buf,
-                                 LocalHandle* acquire_fence) {
-  ALOGD_IF(TRACE, "ConsumerQueue::OnBufferReady: queue_id=%d buffer_id=%d",
-           id(), buf->id());
-  auto buffer = std::static_pointer_cast<BufferConsumer>(buf);
-  return buffer->Acquire(acquire_fence, meta_buffer_tmp_.get(), meta_size_);
+Status<BufferHubQueue::Entry> ConsumerQueue::OnBufferReady(
+    const std::shared_ptr<BufferHubBuffer>& buffer, size_t slot) {
+  ALOGD_IF(TRACE,
+           "ConsumerQueue::OnBufferReady: queue_id=%d buffer_id=%d slot=%zu",
+           id(), buffer->id(), slot);
+
+  // Avoid taking a transient reference, buffer is valid for the duration of
+  // this method call.
+  auto* consumer_buffer = static_cast<BufferConsumer*>(buffer.get());
+  std::unique_ptr<uint8_t[]> metadata(meta_size_ ? new uint8_t[meta_size_]
+                                                 : nullptr);
+  LocalHandle acquire_fence;
+
+  const int ret =
+      consumer_buffer->Acquire(&acquire_fence, metadata.get(), meta_size_);
+  if (ret < 0)
+    return ErrorStatus(-ret);
+  else
+    return {{buffer, std::move(metadata), std::move(acquire_fence), slot}};
 }
 
 Status<void> ConsumerQueue::OnBufferAllocated() {
+  ALOGD_IF(TRACE, "ConsumerQueue::OnBufferAllocated: queue_id=%d", id());
+
   auto status = ImportBuffers();
   if (!status) {
     ALOGE("ConsumerQueue::OnBufferAllocated: Failed to import buffers: %s",
diff --git a/libs/vr/libbufferhubqueue/buffer_hub_queue_producer.cpp b/libs/vr/libbufferhubqueue/buffer_hub_queue_producer.cpp
index 87efeed..932aa37 100644
--- a/libs/vr/libbufferhubqueue/buffer_hub_queue_producer.cpp
+++ b/libs/vr/libbufferhubqueue/buffer_hub_queue_producer.cpp
@@ -159,6 +159,8 @@
   for (size_t retry = 0; retry < BufferHubQueue::kMaxQueueCapacity; retry++) {
     LocalHandle fence;
     auto buffer_status = queue_->Dequeue(dequeue_timeout_ms_, &slot, &fence);
+    if (!buffer_status)
+      return NO_MEMORY;
 
     buffer_producer = buffer_status.take();
     if (!buffer_producer)
@@ -608,10 +610,12 @@
                                                 PixelFormat format,
                                                 uint64_t usage) {
   size_t slot;
-
-  if (queue_->AllocateBuffer(width, height, layer_count, format, usage, &slot) <
-      0) {
-    ALOGE("Failed to allocate new buffer in BufferHub.");
+  auto status =
+      queue_->AllocateBuffer(width, height, layer_count, format, usage, &slot);
+  if (!status) {
+    ALOGE(
+        "BufferHubQueueProducer::AllocateBuffer: Failed to allocate buffer: %s",
+        status.GetErrorMessage().c_str());
     return NO_MEMORY;
   }
 
@@ -626,11 +630,11 @@
 }
 
 status_t BufferHubQueueProducer::RemoveBuffer(size_t slot) {
-  int ret = queue_->DetachBuffer(slot);
-  if (ret < 0) {
-    ALOGE("BufferHubQueueProducer::RemoveBuffer failed through RPC, ret=%s",
-          strerror(-ret));
-    return ret;
+  auto status = queue_->DetachBuffer(slot);
+  if (!status) {
+    ALOGE("BufferHubQueueProducer::RemoveBuffer: Failed to detach buffer: %s",
+          status.GetErrorMessage().c_str());
+    return INVALID_OPERATION;
   }
 
   // Reset in memory objects related the the buffer.
diff --git a/libs/vr/libbufferhubqueue/include/private/dvr/buffer_hub_queue_client.h b/libs/vr/libbufferhubqueue/include/private/dvr/buffer_hub_queue_client.h
index ed67f79..d8d326b 100644
--- a/libs/vr/libbufferhubqueue/include/private/dvr/buffer_hub_queue_client.h
+++ b/libs/vr/libbufferhubqueue/include/private/dvr/buffer_hub_queue_client.h
@@ -21,45 +21,39 @@
 // automatically re-requeued when released by the remote side.
 class BufferHubQueue : public pdx::Client {
  public:
-  using LocalHandle = pdx::LocalHandle;
-  using LocalChannelHandle = pdx::LocalChannelHandle;
-  template <typename T>
-  using Status = pdx::Status<T>;
-
   virtual ~BufferHubQueue() {}
-  void Initialize();
 
-  // Create a new consumer queue that is attached to the producer. Returns
+  // Creates a new consumer queue that is attached to the producer. Returns
   // a new consumer queue client or nullptr on failure.
   std::unique_ptr<ConsumerQueue> CreateConsumerQueue();
 
-  // Create a new consumer queue that is attached to the producer. This queue
+  // Creates a new consumer queue that is attached to the producer. This queue
   // sets each of its imported consumer buffers to the ignored state to avoid
   // participation in lifecycle events.
   std::unique_ptr<ConsumerQueue> CreateSilentConsumerQueue();
 
-  // Return the default buffer width of this buffer queue.
+  // Returns the default buffer width of this buffer queue.
   size_t default_width() const { return default_width_; }
 
-  // Return the default buffer height of this buffer queue.
+  // Returns the default buffer height of this buffer queue.
   size_t default_height() const { return default_height_; }
 
-  // Return the default buffer format of this buffer queue.
+  // Returns the default buffer format of this buffer queue.
   int32_t default_format() const { return default_format_; }
 
-  // Create a new consumer in handle form for immediate transport over RPC.
-  Status<LocalChannelHandle> CreateConsumerQueueHandle();
+  // Creates a new consumer in handle form for immediate transport over RPC.
+  pdx::Status<pdx::LocalChannelHandle> CreateConsumerQueueHandle();
 
-  // Return the number of buffers avaiable for dequeue.
+  // Returns the number of buffers avaiable for dequeue.
   size_t count() const { return available_buffers_.GetSize(); }
 
-  // Return the total number of buffers that the queue is tracking.
+  // Returns the total number of buffers that the queue is tracking.
   size_t capacity() const { return capacity_; }
 
-  // Return the size of metadata structure associated with this BufferBubQueue.
+  // Returns the size of metadata structure associated with this queue.
   size_t metadata_size() const { return meta_size_; }
 
-  // Return whether the buffer queue is alrady full.
+  // Returns whether the buffer queue is full.
   bool is_full() const { return available_buffers_.IsFull(); }
 
   explicit operator bool() const { return epoll_fd_.IsValid(); }
@@ -68,7 +62,7 @@
     return buffers_[slot];
   }
 
-  Status<int> GetEventMask(int events) {
+  pdx::Status<int> GetEventMask(int events) {
     if (auto* client_channel = GetChannel()) {
       return client_channel->GetEventMask(events);
     } else {
@@ -86,81 +80,95 @@
   // occurred.
   bool HandleQueueEvents() { return WaitForBuffers(0); }
 
-  // Enqueue a buffer marks buffer to be available (|Gain|'ed for producer
-  // and |Acquire|'ed for consumer. This is only used for internal bookkeeping.
-  void Enqueue(const std::shared_ptr<BufferHubBuffer>& buf, size_t slot);
-
-  // |BufferHubQueue| will keep track of at most this value of buffers.
+  // The queue tracks at most this many buffers.
   static constexpr size_t kMaxQueueCapacity =
       android::BufferQueueDefs::NUM_BUFFER_SLOTS;
 
-  // Special epoll data field indicating that the epoll event refers to the
-  // queue.
-  static constexpr int64_t kEpollQueueEventIndex = -1;
-
-  // When pass |kNoTimeout| to |Dequeue|, it will block indefinitely without a
-  // timeout.
   static constexpr int kNoTimeOut = -1;
 
   int id() const { return id_; }
   bool hung_up() const { return hung_up_; }
 
  protected:
-  BufferHubQueue(LocalChannelHandle channel);
+  BufferHubQueue(pdx::LocalChannelHandle channel);
   BufferHubQueue(const std::string& endpoint_path);
 
   // Imports the queue parameters by querying BufferHub for the parameters for
   // this channel.
-  Status<void> ImportQueue();
+  pdx::Status<void> ImportQueue();
 
   // Sets up the queue with the given parameters.
   void SetupQueue(size_t meta_size_bytes_, int id);
 
-  // Called by ProducerQueue::AddBuffer and ConsumerQueue::AddBuffer only. to
-  // register a buffer for epoll and internal bookkeeping.
-  int AddBuffer(const std::shared_ptr<BufferHubBuffer>& buf, size_t slot);
+  // Register a buffer for management by the queue. Used by subclasses to add a
+  // buffer to internal bookkeeping.
+  pdx::Status<void> AddBuffer(const std::shared_ptr<BufferHubBuffer>& buffer,
+                              size_t slot);
 
-  // Called by ProducerQueue::DetachBuffer and ConsumerQueue::DetachBuffer only.
+  // Called by ProducerQueue::DetachBuffer and ConsumerQueue::DetachBuffer only
   // to deregister a buffer for epoll and internal bookkeeping.
-  virtual int DetachBuffer(size_t slot);
+  virtual pdx::Status<void> DetachBuffer(size_t slot);
 
   // Dequeue a buffer from the free queue, blocking until one is available. The
   // timeout argument specifies the number of milliseconds that |Dequeue()| will
-  // block. Specifying a timeout of -1 causes |Dequeue()| to block indefinitely,
-  // while specifying a timeout equal to zero cause |Dequeue()| to return
+  // block. Specifying a timeout of -1 causes Dequeue() to block indefinitely,
+  // while specifying a timeout equal to zero cause Dequeue() to return
   // immediately, even if no buffers are available.
-  pdx::Status<std::shared_ptr<BufferHubBuffer>> Dequeue(int timeout,
-                                                        size_t* slot,
-                                                        void* meta,
-                                                        LocalHandle* fence);
+  pdx::Status<std::shared_ptr<BufferHubBuffer>> Dequeue(
+      int timeout, size_t* slot, void* meta, pdx::LocalHandle* fence);
 
-  // Wait for buffers to be released and re-add them to the queue.
+  // Waits for buffers to become available and adds them to the available queue.
   bool WaitForBuffers(int timeout);
-  void HandleBufferEvent(size_t slot, int poll_events);
-  void HandleQueueEvent(int poll_events);
 
-  virtual int OnBufferReady(const std::shared_ptr<BufferHubBuffer>& buf,
-                            LocalHandle* fence) = 0;
+  pdx::Status<void> HandleBufferEvent(size_t slot, int event_fd,
+                                      int poll_events);
+  pdx::Status<void> HandleQueueEvent(int poll_events);
+
+  // Entry in the ring buffer of available buffers that stores related
+  // per-buffer data.
+  struct Entry {
+    Entry() : slot(0) {}
+    Entry(const std::shared_ptr<BufferHubBuffer>& buffer, size_t slot)
+        : buffer(buffer), slot(slot) {}
+    Entry(const std::shared_ptr<BufferHubBuffer>& buffer,
+          std::unique_ptr<uint8_t[]> metadata, pdx::LocalHandle fence,
+          size_t slot)
+        : buffer(buffer),
+          metadata(std::move(metadata)),
+          fence(std::move(fence)),
+          slot(slot) {}
+    Entry(Entry&&) = default;
+    Entry& operator=(Entry&&) = default;
+
+    std::shared_ptr<BufferHubBuffer> buffer;
+    std::unique_ptr<uint8_t[]> metadata;
+    pdx::LocalHandle fence;
+    size_t slot;
+  };
+
+  // Enqueues a buffer to the available list (Gained for producer or Acquireed
+  // for consumer).
+  pdx::Status<void> Enqueue(Entry entry);
+
+  virtual pdx::Status<Entry> OnBufferReady(
+      const std::shared_ptr<BufferHubBuffer>& buf, size_t slot) = 0;
 
   // Called when a buffer is allocated remotely.
-  virtual Status<void> OnBufferAllocated() { return {}; }
+  virtual pdx::Status<void> OnBufferAllocated() { return {}; }
 
-  // Data members to handle arbitrary metadata passed through BufferHub. It is
-  // fair to enforce that all buffers in the same queue share the same metadata
-  // type. |meta_size_| is used to store the size of metadata on queue creation;
-  // and |meta_buffer_tmp_| is allocated and resized to |meta_size_| on queue
-  // creation to be later used as temporary space so that we can avoid
-  // additional dynamic memory allocation in each |Enqueue| and |Dequeue| call.
-  size_t meta_size_;
-
-  // Here we intentionally choose |unique_ptr<uint8_t[]>| over vector<uint8_t>
-  // to disallow dynamic resizing for stability reasons.
-  std::unique_ptr<uint8_t[]> meta_buffer_tmp_;
+  // Size of the metadata that buffers in this queue cary.
+  size_t meta_size_{0};
 
  private:
+  void Initialize();
+
+  // Special epoll data field indicating that the epoll event refers to the
+  // queue.
+  static constexpr int64_t kEpollQueueEventIndex = -1;
+
   static constexpr size_t kMaxEvents = 128;
 
-  // The |u64| data field of an epoll event is interpreted as int64_t:
+  // The u64 data field of an epoll event is interpreted as int64_t:
   // When |index| >= 0 and |index| < kMaxQueueCapacity it refers to a specific
   // element of |buffers_| as a direct index;
   static bool is_buffer_event_index(int64_t index) {
@@ -168,47 +176,11 @@
            index < static_cast<int64_t>(BufferHubQueue::kMaxQueueCapacity);
   }
 
-  // When |index| == kEpollQueueEventIndex, it refers to the queue itself.
+  // When |index| == kEpollQueueEventIndex it refers to the queue itself.
   static bool is_queue_event_index(int64_t index) {
     return index == BufferHubQueue::kEpollQueueEventIndex;
   }
 
-  struct BufferInfo {
-    // A logical slot number that is assigned to a buffer at allocation time.
-    // The slot number remains unchanged during the entire life cycle of the
-    // buffer and should not be confused with the enqueue and dequeue order.
-    size_t slot;
-
-    // A BufferHubBuffer client.
-    std::shared_ptr<BufferHubBuffer> buffer;
-
-    // Metadata associated with the buffer.
-    std::unique_ptr<uint8_t[]> metadata;
-
-    BufferInfo() : BufferInfo(-1, 0) {}
-
-    BufferInfo(size_t slot, size_t metadata_size)
-        : slot(slot),
-          buffer(nullptr),
-          metadata(metadata_size ? new uint8_t[metadata_size] : nullptr) {}
-
-    BufferInfo(BufferInfo&& other)
-        : slot(other.slot),
-          buffer(std::move(other.buffer)),
-          metadata(std::move(other.metadata)) {}
-
-    BufferInfo& operator=(BufferInfo&& other) {
-      slot = other.slot;
-      buffer = std::move(other.buffer);
-      metadata = std::move(other.metadata);
-      return *this;
-    }
-
-   private:
-    BufferInfo(const BufferInfo&) = delete;
-    void operator=(BufferInfo&) = delete;
-  };
-
   // Default buffer width that can be set to override the buffer width when a
   // width and height of 0 are specified in AllocateBuffer.
   size_t default_width_{1};
@@ -221,49 +193,18 @@
   // isn't specified in AllocateBuffer.
   int32_t default_format_{PIXEL_FORMAT_RGBA_8888};
 
-  // Buffer queue:
-  // |buffers_| tracks all |BufferHubBuffer|s created by this |BufferHubQueue|.
-  std::vector<std::shared_ptr<BufferHubBuffer>> buffers_;
+  // Tracks the buffers belonging to this queue. Buffers are stored according to
+  // "slot" in this vector. Each slot is a logical id of the buffer within this
+  // queue regardless of its queue position or presence in the ring buffer.
+  std::vector<std::shared_ptr<BufferHubBuffer>> buffers_{kMaxQueueCapacity};
 
-  // |epollhup_pending_| tracks whether a slot of |buffers_| get detached before
-  // its corresponding EPOLLHUP event got handled. This could happen as the
-  // following sequence:
-  // 1. Producer queue's client side allocates a new buffer (at slot 1).
-  // 2. Producer queue's client side replaces an existing buffer (at slot 0).
-  //    This is implemented by first detaching the buffer and then allocating a
-  //    new buffer.
-  // 3. During the same epoll_wait, Consumer queue's client side gets EPOLLIN
-  //    event on the queue which indicates a new buffer is available and the
-  //    EPOLLHUP event for slot 0. Consumer handles these two events in order.
-  // 4. Consumer client calls BufferHubRPC::ConsumerQueueImportBuffers and both
-  //    slot 0 and (the new) slot 1 buffer will be imported. During the import
-  //    of the buffer at slot 1, consumer client detaches the old buffer so that
-  //    the new buffer can be registered. At the same time
-  //    |epollhup_pending_[slot]| is marked to indicate that buffer at this slot
-  //    was detached prior to EPOLLHUP event.
-  // 5. Consumer client continues to handle the EPOLLHUP. Since
-  //    |epollhup_pending_[slot]| is marked as true, it can safely ignore the
-  //    event without detaching the newly allocated buffer at slot 1.
-  //
-  // In normal situations where the previously described sequence doesn't
-  // happen, an EPOLLHUP event should trigger a regular buffer detach.
-  std::vector<bool> epollhup_pending_;
+  // Buffers and related data that are available for dequeue.
+  RingBuffer<Entry> available_buffers_{kMaxQueueCapacity};
 
-  // |available_buffers_| uses |dvr::RingBuffer| to implementation queue
-  // sematics. When |Dequeue|, we pop the front element from
-  // |available_buffers_|, and  that buffer's reference count will decrease by
-  // one, while another reference in |buffers_| keeps the last reference to
-  // prevent the buffer from being deleted.
-  RingBuffer<BufferInfo> available_buffers_;
+  // Keeps track with how many buffers have been added into the queue.
+  size_t capacity_{0};
 
-  // Fences (acquire fence for consumer and release fence for consumer) , one
-  // for each buffer slot.
-  std::vector<LocalHandle> fences_;
-
-  // Keep track with how many buffers have been added into the queue.
-  size_t capacity_;
-
-  // Epoll fd used to wait for BufferHub events.
+  // Epoll fd used to manage buffer events.
   EpollFileDescriptor epoll_fd_;
 
   // Flag indicating that the other side hung up. For ProducerQueues this
@@ -273,7 +214,7 @@
   bool hung_up_{false};
 
   // Global id for the queue that is consistent across processes.
-  int id_;
+  int id_{-1};
 
   BufferHubQueue(const BufferHubQueue&) = delete;
   void operator=(BufferHubQueue&) = delete;
@@ -317,15 +258,15 @@
                         usage_deny_set_mask, usage_deny_clear_mask);
   }
 
-  // Import a |ProducerQueue| from a channel handle.
-  static std::unique_ptr<ProducerQueue> Import(LocalChannelHandle handle) {
+  // Import a ProducerQueue from a channel handle.
+  static std::unique_ptr<ProducerQueue> Import(pdx::LocalChannelHandle handle) {
     return BASE::Create(std::move(handle));
   }
 
   // Get a buffer producer. Note that the method doesn't check whether the
   // buffer slot has a valid buffer that has been allocated already. When no
-  // buffer has been imported before it returns |nullptr|; otherwise it returns
-  // a shared pointer to a |BufferProducer|.
+  // buffer has been imported before it returns nullptr; otherwise it returns
+  // a shared pointer to a BufferProducer.
   std::shared_ptr<BufferProducer> GetBuffer(size_t slot) const {
     return std::static_pointer_cast<BufferProducer>(
         BufferHubQueue::GetBuffer(slot));
@@ -333,26 +274,30 @@
 
   // Allocate producer buffer to populate the queue. Once allocated, a producer
   // buffer is automatically enqueue'd into the ProducerQueue and available to
-  // use (i.e. in |Gain|'ed mode).
-  // Returns Zero on success and negative error code when buffer allocation
-  // fails.
-  int AllocateBuffer(uint32_t width, uint32_t height, uint32_t layer_count,
-                     uint32_t format, uint64_t usage, size_t* out_slot);
+  // use (i.e. in GAINED state).
+  pdx::Status<void> AllocateBuffer(uint32_t width, uint32_t height,
+                                   uint32_t layer_count, uint32_t format,
+                                   uint64_t usage, size_t* out_slot);
 
   // Add a producer buffer to populate the queue. Once added, a producer buffer
-  // is available to use (i.e. in |Gain|'ed mode).
-  int AddBuffer(const std::shared_ptr<BufferProducer>& buf, size_t slot);
+  // is available to use (i.e. in GAINED state).
+  pdx::Status<void> AddBuffer(const std::shared_ptr<BufferProducer>& buffer,
+                              size_t slot);
 
   // Detach producer buffer from the queue.
-  // Returns Zero on success and negative error code when buffer detach
-  // fails.
-  int DetachBuffer(size_t slot) override;
+  pdx::Status<void> DetachBuffer(size_t slot) override;
 
   // Dequeue a producer buffer to write. The returned buffer in |Gain|'ed mode,
   // and caller should call Post() once it's done writing to release the buffer
   // to the consumer side.
   pdx::Status<std::shared_ptr<BufferProducer>> Dequeue(
-      int timeout, size_t* slot, LocalHandle* release_fence);
+      int timeout, size_t* slot, pdx::LocalHandle* release_fence);
+
+  // Enqueues a producer buffer in the queue.
+  pdx::Status<void> Enqueue(const std::shared_ptr<BufferProducer>& buffer,
+                            size_t slot) {
+    return BufferHubQueue::Enqueue({buffer, slot});
+  }
 
  private:
   friend BASE;
@@ -361,13 +306,13 @@
   // static template methods inherited from ClientBase, which take the same
   // arguments as the constructors.
   explicit ProducerQueue(size_t meta_size);
-  ProducerQueue(LocalChannelHandle handle);
+  explicit ProducerQueue(pdx::LocalChannelHandle handle);
   ProducerQueue(size_t meta_size, uint64_t usage_set_mask,
                 uint64_t usage_clear_mask, uint64_t usage_deny_set_mask,
                 uint64_t usage_deny_clear_mask);
 
-  int OnBufferReady(const std::shared_ptr<BufferHubBuffer>& buf,
-                    LocalHandle* release_fence) override;
+  pdx::Status<Entry> OnBufferReady(
+      const std::shared_ptr<BufferHubBuffer>& buffer, size_t slot) override;
 };
 
 // Explicit specializations of ProducerQueue::Create for void metadata type.
@@ -399,7 +344,7 @@
   // used to avoid participation in the buffer lifecycle by a consumer queue
   // that is only used to spawn other consumer queues, such as in an
   // intermediate service.
-  static std::unique_ptr<ConsumerQueue> Import(LocalChannelHandle handle,
+  static std::unique_ptr<ConsumerQueue> Import(pdx::LocalChannelHandle handle,
                                                bool ignore_on_import = false) {
     return std::unique_ptr<ConsumerQueue>(
         new ConsumerQueue(std::move(handle), ignore_on_import));
@@ -407,7 +352,7 @@
 
   // Import newly created buffers from the service side.
   // Returns number of buffers successfully imported or an error.
-  Status<size_t> ImportBuffers();
+  pdx::Status<size_t> ImportBuffers();
 
   // Dequeue a consumer buffer to read. The returned buffer in |Acquired|'ed
   // mode, and caller should call Releasse() once it's done writing to release
@@ -417,33 +362,34 @@
   // when the buffer is orignally created.
   template <typename Meta>
   pdx::Status<std::shared_ptr<BufferConsumer>> Dequeue(
-      int timeout, size_t* slot, Meta* meta, LocalHandle* acquire_fence) {
+      int timeout, size_t* slot, Meta* meta, pdx::LocalHandle* acquire_fence) {
     return Dequeue(timeout, slot, meta, sizeof(*meta), acquire_fence);
   }
   pdx::Status<std::shared_ptr<BufferConsumer>> Dequeue(
-      int timeout, size_t* slot, LocalHandle* acquire_fence) {
+      int timeout, size_t* slot, pdx::LocalHandle* acquire_fence) {
     return Dequeue(timeout, slot, nullptr, 0, acquire_fence);
   }
 
   pdx::Status<std::shared_ptr<BufferConsumer>> Dequeue(
       int timeout, size_t* slot, void* meta, size_t meta_size,
-      LocalHandle* acquire_fence);
+      pdx::LocalHandle* acquire_fence);
 
  private:
   friend BufferHubQueue;
 
-  ConsumerQueue(LocalChannelHandle handle, bool ignore_on_import = false);
+  ConsumerQueue(pdx::LocalChannelHandle handle, bool ignore_on_import = false);
 
   // Add a consumer buffer to populate the queue. Once added, a consumer buffer
   // is NOT available to use until the producer side |Post| it. |WaitForBuffers|
   // will catch the |Post| and |Acquire| the buffer to make it available for
   // consumer.
-  int AddBuffer(const std::shared_ptr<BufferConsumer>& buf, size_t slot);
+  pdx::Status<void> AddBuffer(const std::shared_ptr<BufferConsumer>& buffer,
+                              size_t slot);
 
-  int OnBufferReady(const std::shared_ptr<BufferHubBuffer>& buf,
-                    LocalHandle* acquire_fence) override;
+  pdx::Status<Entry> OnBufferReady(
+      const std::shared_ptr<BufferHubBuffer>& buffer, size_t slot) override;
 
-  Status<void> OnBufferAllocated() override;
+  pdx::Status<void> OnBufferAllocated() override;
 
   // Flag indicating that imported (consumer) buffers should be ignored when
   // imported to avoid participating in the buffer ownership flow.
diff --git a/libs/vr/libbufferhubqueue/tests/buffer_hub_queue-test.cpp b/libs/vr/libbufferhubqueue/tests/buffer_hub_queue-test.cpp
index fe0b12a..ff2e146 100644
--- a/libs/vr/libbufferhubqueue/tests/buffer_hub_queue-test.cpp
+++ b/libs/vr/libbufferhubqueue/tests/buffer_hub_queue-test.cpp
@@ -6,6 +6,9 @@
 
 #include <vector>
 
+// Enable/disable debug logging.
+#define TRACE 0
+
 namespace android {
 namespace dvr {
 
@@ -51,13 +54,16 @@
            CreateConsumerQueue();
   }
 
-  void AllocateBuffer() {
+  void AllocateBuffer(size_t* slot_out = nullptr) {
     // Create producer buffer.
     size_t slot;
-    int ret = producer_queue_->AllocateBuffer(kBufferWidth, kBufferHeight,
-                                              kBufferLayerCount, kBufferFormat,
-                                              kBufferUsage, &slot);
-    ASSERT_EQ(ret, 0);
+    auto status = producer_queue_->AllocateBuffer(
+        kBufferWidth, kBufferHeight, kBufferLayerCount, kBufferFormat,
+        kBufferUsage, &slot);
+    ASSERT_TRUE(status.ok());
+
+    if (slot_out)
+      *slot_out = slot;
   }
 
  protected:
@@ -94,13 +100,13 @@
 }
 
 TEST_F(BufferHubQueueTest, TestProducerConsumer) {
-  const size_t nb_buffer = 16;
+  const size_t kBufferCount = 16;
   size_t slot;
   uint64_t seq;
 
   ASSERT_TRUE(CreateQueues<uint64_t>());
 
-  for (size_t i = 0; i < nb_buffer; i++) {
+  for (size_t i = 0; i < kBufferCount; i++) {
     AllocateBuffer();
 
     // Producer queue has all the available buffers on initialize.
@@ -120,14 +126,23 @@
     ASSERT_EQ(consumer_queue_->capacity(), i + 1);
   }
 
-  for (size_t i = 0; i < nb_buffer; i++) {
+  // Use /dev/zero as a stand-in for a fence. As long as BufferHub does not need
+  // to merge fences, which only happens when multiple consumers release the
+  // same buffer with release fences, the file object should simply pass
+  // through.
+  LocalHandle post_fence("/dev/zero", O_RDONLY);
+  struct stat post_fence_stat;
+  ASSERT_EQ(0, fstat(post_fence.Get(), &post_fence_stat));
+
+  for (size_t i = 0; i < kBufferCount; i++) {
     LocalHandle fence;
-    // First time, there is no buffer available to dequeue.
+
+    // First time there is no buffer available to dequeue.
     auto consumer_status = consumer_queue_->Dequeue(0, &slot, &seq, &fence);
     ASSERT_FALSE(consumer_status.ok());
     ASSERT_EQ(ETIMEDOUT, consumer_status.error());
 
-    // Make sure Producer buffer is Post()'ed so that it's ready to Accquire
+    // Make sure Producer buffer is POSTED so that it's ready to Accquire
     // in the consumer's Dequeue() function.
     auto producer_status = producer_queue_->Dequeue(0, &slot, &fence);
     ASSERT_TRUE(producer_status.ok());
@@ -135,18 +150,133 @@
     ASSERT_NE(nullptr, producer);
 
     uint64_t seq_in = static_cast<uint64_t>(i);
-    ASSERT_EQ(producer->Post({}, &seq_in, sizeof(seq_in)), 0);
+    ASSERT_EQ(producer->Post(post_fence, &seq_in, sizeof(seq_in)), 0);
 
-    // Second time, the just |Post()|'ed buffer should be dequeued.
+    // Second time the just the POSTED buffer should be dequeued.
     uint64_t seq_out = 0;
     consumer_status = consumer_queue_->Dequeue(0, &slot, &seq_out, &fence);
     ASSERT_TRUE(consumer_status.ok());
+    EXPECT_TRUE(fence.IsValid());
+
+    struct stat acquire_fence_stat;
+    ASSERT_EQ(0, fstat(fence.Get(), &acquire_fence_stat));
+
+    // The file descriptors should refer to the same file object. Testing the
+    // device id and inode is a proxy for testing that the fds refer to the same
+    // file object.
+    EXPECT_NE(post_fence.Get(), fence.Get());
+    EXPECT_EQ(post_fence_stat.st_dev, acquire_fence_stat.st_dev);
+    EXPECT_EQ(post_fence_stat.st_ino, acquire_fence_stat.st_ino);
+
     auto consumer = consumer_status.take();
     ASSERT_NE(nullptr, consumer);
     ASSERT_EQ(seq_in, seq_out);
   }
 }
 
+TEST_F(BufferHubQueueTest, TestDetach) {
+  ASSERT_TRUE(CreateProducerQueue<void>());
+
+  // Allocate buffers.
+  const size_t kBufferCount = 4u;
+  for (size_t i = 0; i < kBufferCount; i++) {
+    AllocateBuffer();
+  }
+  ASSERT_EQ(kBufferCount, producer_queue_->count());
+  ASSERT_EQ(kBufferCount, producer_queue_->capacity());
+
+  consumer_queue_ = producer_queue_->CreateConsumerQueue();
+  ASSERT_NE(nullptr, consumer_queue_);
+
+  // Check that buffers are correctly imported on construction.
+  EXPECT_EQ(kBufferCount, consumer_queue_->capacity());
+  EXPECT_EQ(0u, consumer_queue_->count());
+
+  // Dequeue all the buffers and keep track of them in an array. This prevents
+  // the producer queue ring buffer ref counts from interfering with the tests.
+  struct Entry {
+    std::shared_ptr<BufferProducer> buffer;
+    LocalHandle fence;
+    size_t slot;
+  };
+  std::array<Entry, kBufferCount> buffers;
+
+  for (size_t i = 0; i < kBufferCount; i++) {
+    Entry* entry = &buffers[i];
+    auto producer_status =
+        producer_queue_->Dequeue(0, &entry->slot, &entry->fence);
+    ASSERT_TRUE(producer_status.ok());
+    entry->buffer = producer_status.take();
+    ASSERT_NE(nullptr, entry->buffer);
+    EXPECT_EQ(i, entry->slot);
+  }
+
+  // Detach a buffer and make sure both queues reflect the change.
+  ASSERT_TRUE(producer_queue_->DetachBuffer(buffers[0].slot));
+  EXPECT_EQ(kBufferCount - 1, producer_queue_->capacity());
+
+  // As long as the detached buffer is still alive the consumer queue won't know
+  // its gone.
+  EXPECT_EQ(kBufferCount, consumer_queue_->capacity());
+  EXPECT_FALSE(consumer_queue_->HandleQueueEvents());
+  EXPECT_EQ(kBufferCount, consumer_queue_->capacity());
+
+  // Release the detached buffer.
+  buffers[0].buffer = nullptr;
+
+  // Now the consumer queue should know it's gone.
+  EXPECT_FALSE(consumer_queue_->HandleQueueEvents());
+  EXPECT_EQ(kBufferCount - 1, consumer_queue_->capacity());
+
+  // Allocate a new buffer. This should take the first empty slot.
+  size_t slot;
+  AllocateBuffer(&slot);
+  ALOGE_IF(TRACE, "ALLOCATE %zu", slot);
+  EXPECT_EQ(buffers[0].slot, slot);
+  EXPECT_EQ(kBufferCount, producer_queue_->capacity());
+
+  // The consumer queue should pick up the new buffer.
+  EXPECT_EQ(kBufferCount - 1, consumer_queue_->capacity());
+  EXPECT_FALSE(consumer_queue_->HandleQueueEvents());
+  EXPECT_EQ(kBufferCount, consumer_queue_->capacity());
+
+  // Detach and allocate a buffer.
+  ASSERT_TRUE(producer_queue_->DetachBuffer(buffers[1].slot));
+  EXPECT_EQ(kBufferCount - 1, producer_queue_->capacity());
+  buffers[1].buffer = nullptr;
+
+  AllocateBuffer(&slot);
+  ALOGE_IF(TRACE, "ALLOCATE %zu", slot);
+  EXPECT_EQ(buffers[1].slot, slot);
+  EXPECT_EQ(kBufferCount, producer_queue_->capacity());
+
+  // The consumer queue should pick up the new buffer but the count shouldn't
+  // change.
+  EXPECT_EQ(kBufferCount, consumer_queue_->capacity());
+  EXPECT_FALSE(consumer_queue_->HandleQueueEvents());
+  EXPECT_EQ(kBufferCount, consumer_queue_->capacity());
+
+  // Detach and allocate a buffer, but don't free the buffer right away.
+  ASSERT_TRUE(producer_queue_->DetachBuffer(buffers[2].slot));
+  EXPECT_EQ(kBufferCount - 1, producer_queue_->capacity());
+
+  AllocateBuffer(&slot);
+  ALOGE_IF(TRACE, "ALLOCATE %zu", slot);
+  EXPECT_EQ(buffers[2].slot, slot);
+  EXPECT_EQ(kBufferCount, producer_queue_->capacity());
+
+  EXPECT_EQ(kBufferCount, consumer_queue_->capacity());
+  EXPECT_FALSE(consumer_queue_->HandleQueueEvents());
+  EXPECT_EQ(kBufferCount, consumer_queue_->capacity());
+
+  // Release the producer buffer to trigger a POLLHUP event for an already
+  // detached buffer.
+  buffers[2].buffer = nullptr;
+  EXPECT_EQ(kBufferCount, consumer_queue_->capacity());
+  EXPECT_FALSE(consumer_queue_->HandleQueueEvents());
+  EXPECT_EQ(kBufferCount, consumer_queue_->capacity());
+}
+
 TEST_F(BufferHubQueueTest, TestMultipleConsumers) {
   ASSERT_TRUE(CreateProducerQueue<void>());
 
@@ -347,10 +477,10 @@
 
   // When allocation, leave out |set_mask| from usage bits on purpose.
   size_t slot;
-  int ret = producer_queue_->AllocateBuffer(kBufferWidth, kBufferHeight,
-                                            kBufferFormat, kBufferLayerCount,
-                                            kBufferUsage & ~set_mask, &slot);
-  ASSERT_EQ(0, ret);
+  auto status = producer_queue_->AllocateBuffer(
+      kBufferWidth, kBufferHeight, kBufferLayerCount, kBufferFormat,
+      kBufferUsage & ~set_mask, &slot);
+  ASSERT_TRUE(status.ok());
 
   LocalHandle fence;
   auto p1_status = producer_queue_->Dequeue(0, &slot, &fence);
@@ -365,10 +495,10 @@
 
   // When allocation, add |clear_mask| into usage bits on purpose.
   size_t slot;
-  int ret = producer_queue_->AllocateBuffer(kBufferWidth, kBufferHeight,
-                                            kBufferLayerCount, kBufferFormat,
-                                            kBufferUsage | clear_mask, &slot);
-  ASSERT_EQ(0, ret);
+  auto status = producer_queue_->AllocateBuffer(
+      kBufferWidth, kBufferHeight, kBufferLayerCount, kBufferFormat,
+      kBufferUsage | clear_mask, &slot);
+  ASSERT_TRUE(status.ok());
 
   LocalHandle fence;
   auto p1_status = producer_queue_->Dequeue(0, &slot, &fence);
@@ -384,16 +514,17 @@
   // Now that |deny_set_mask| is illegal, allocation without those bits should
   // be able to succeed.
   size_t slot;
-  int ret = producer_queue_->AllocateBuffer(
+  auto status = producer_queue_->AllocateBuffer(
       kBufferWidth, kBufferHeight, kBufferLayerCount, kBufferFormat,
       kBufferUsage & ~deny_set_mask, &slot);
-  ASSERT_EQ(ret, 0);
+  ASSERT_TRUE(status.ok());
 
   // While allocation with those bits should fail.
-  ret = producer_queue_->AllocateBuffer(kBufferWidth, kBufferHeight,
-                                        kBufferLayerCount, kBufferFormat,
-                                        kBufferUsage | deny_set_mask, &slot);
-  ASSERT_EQ(ret, -EINVAL);
+  status = producer_queue_->AllocateBuffer(kBufferWidth, kBufferHeight,
+                                           kBufferLayerCount, kBufferFormat,
+                                           kBufferUsage | deny_set_mask, &slot);
+  ASSERT_FALSE(status.ok());
+  ASSERT_EQ(EINVAL, status.error());
 }
 
 TEST_F(BufferHubQueueTest, TestUsageDenyClearMask) {
@@ -403,16 +534,17 @@
   // Now that clearing |deny_clear_mask| is illegal (i.e. setting these bits are
   // mandatory), allocation with those bits should be able to succeed.
   size_t slot;
-  int ret = producer_queue_->AllocateBuffer(
+  auto status = producer_queue_->AllocateBuffer(
       kBufferWidth, kBufferHeight, kBufferLayerCount, kBufferFormat,
       kBufferUsage | deny_clear_mask, &slot);
-  ASSERT_EQ(ret, 0);
+  ASSERT_TRUE(status.ok());
 
   // While allocation without those bits should fail.
-  ret = producer_queue_->AllocateBuffer(kBufferWidth, kBufferHeight,
-                                        kBufferLayerCount, kBufferFormat,
-                                        kBufferUsage & ~deny_clear_mask, &slot);
-  ASSERT_EQ(ret, -EINVAL);
+  status = producer_queue_->AllocateBuffer(
+      kBufferWidth, kBufferHeight, kBufferLayerCount, kBufferFormat,
+      kBufferUsage & ~deny_clear_mask, &slot);
+  ASSERT_FALSE(status.ok());
+  ASSERT_EQ(EINVAL, status.error());
 }
 
 }  // namespace
diff --git a/libs/vr/libbufferhubqueue/tests/buffer_hub_queue_producer-test.cpp b/libs/vr/libbufferhubqueue/tests/buffer_hub_queue_producer-test.cpp
index 2b6239f..c7692d0 100644
--- a/libs/vr/libbufferhubqueue/tests/buffer_hub_queue_producer-test.cpp
+++ b/libs/vr/libbufferhubqueue/tests/buffer_hub_queue_producer-test.cpp
@@ -192,7 +192,7 @@
   EXPECT_EQ(NO_ERROR,
             mProducer->query(NATIVE_WINDOW_MIN_UNDEQUEUED_BUFFERS, &value));
   EXPECT_LE(0, value);
-  EXPECT_GE(BufferQueueDefs::NUM_BUFFER_SLOTS, static_cast<size_t>(value));
+  EXPECT_GE(BufferQueueDefs::NUM_BUFFER_SLOTS, value);
 
   EXPECT_EQ(NO_ERROR,
             mProducer->query(NATIVE_WINDOW_CONSUMER_RUNNING_BEHIND, &value));
diff --git a/libs/vr/libdisplay/display_client.cpp b/libs/vr/libdisplay/display_client.cpp
index 935ca2e..72db0dc 100644
--- a/libs/vr/libdisplay/display_client.cpp
+++ b/libs/vr/libdisplay/display_client.cpp
@@ -138,13 +138,13 @@
   ALOGD_IF(TRACE, "Surface::CreateQueue: Allocating %zu buffers...", capacity);
   for (size_t i = 0; i < capacity; i++) {
     size_t slot;
-    const int ret = producer_queue->AllocateBuffer(width, height, layer_count,
-                                                   format, usage, &slot);
-    if (ret < 0) {
+    auto allocate_status = producer_queue->AllocateBuffer(
+        width, height, layer_count, format, usage, &slot);
+    if (!allocate_status) {
       ALOGE(
           "Surface::CreateQueue: Failed to allocate buffer on queue_id=%d: %s",
-          producer_queue->id(), strerror(-ret));
-      return ErrorStatus(ENOMEM);
+          producer_queue->id(), allocate_status.GetErrorMessage().c_str());
+      return allocate_status.error_status();
     }
     ALOGD_IF(
         TRACE,
diff --git a/libs/vr/libdvr/tests/dvr_buffer_queue-test.cpp b/libs/vr/libdvr/tests/dvr_buffer_queue-test.cpp
index 474e968..5d12020 100644
--- a/libs/vr/libdvr/tests/dvr_buffer_queue-test.cpp
+++ b/libs/vr/libdvr/tests/dvr_buffer_queue-test.cpp
@@ -40,10 +40,11 @@
   void AllocateBuffers(size_t buffer_count) {
     size_t out_slot;
     for (size_t i = 0; i < buffer_count; i++) {
-      int ret = GetProducerQueueFromDvrWriteBufferQueue(write_queue_)
-                    ->AllocateBuffer(kBufferWidth, kBufferHeight, kLayerCount,
-                                     kBufferFormat, kBufferUsage, &out_slot);
-      ASSERT_EQ(0, ret);
+      auto status =
+          GetProducerQueueFromDvrWriteBufferQueue(write_queue_)
+              ->AllocateBuffer(kBufferWidth, kBufferHeight, kLayerCount,
+                               kBufferFormat, kBufferUsage, &out_slot);
+      ASSERT_TRUE(status.ok());
     }
   }