drm_hwcomposer: Remove threading

Since HWC2 doesn't require the use of threads to implement correct
synchronization, remove some of these threads.

BUG=None
TEST=Tested on Qemu+drm_hwcomposer

Change-Id: Ia1cfb44648e0d85547cdff2e1a2f5e034bf5f110
Signed-off-by: Robert Foss <robert.foss@collabora.com>

17 files changed, 90 insertions, 1657 deletions

diff --git a/Android.mk b/Android.mk
index 98ce3a6..00a0087 100644
--- a/Android.mk
+++ b/Android.mk
@@ -40,9 +40,6 @@ LOCAL_C_INCLUDES := \
 LOCAL_SRC_FILES := \
 	autolock.cpp \
 	drmresources.cpp \
-	drmcomposition.cpp \
-	drmcompositor.cpp \
-	drmcompositorworker.cpp \
 	drmconnector.cpp \
 	drmcrtc.cpp \
 	drmdisplaycomposition.cpp \
diff --git a/drmcomposition.cpp b/drmcomposition.cpp
deleted file mode 100644
index 1aaf920..0000000
--- a/drmcomposition.cpp
+++ /dev/null
@@ -1,166 +0,0 @@
-/*
- * Copyright (C) 2015 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-#define LOG_TAG "hwc-drm-composition"
-
-#include "drmcomposition.h"
-#include "drmcrtc.h"
-#include "drmplane.h"
-#include "drmresources.h"
-#include "platform.h"
-
-#include <stdlib.h>
-
-#include <cutils/log.h>
-#include <cutils/properties.h>
-#include <sw_sync.h>
-#include <sync/sync.h>
-
-namespace android {
-
-DrmComposition::DrmComposition(DrmResources *drm, Importer *importer,
-                               Planner *planner)
-    : drm_(drm), importer_(importer), planner_(planner) {
-  char use_overlay_planes_prop[PROPERTY_VALUE_MAX];
-  property_get("hwc.drm.use_overlay_planes", use_overlay_planes_prop, "1");
-  bool use_overlay_planes = atoi(use_overlay_planes_prop);
-
-  for (auto &plane : drm->planes()) {
-    if (plane->type() == DRM_PLANE_TYPE_PRIMARY)
-      primary_planes_.push_back(plane.get());
-    else if (use_overlay_planes && plane->type() == DRM_PLANE_TYPE_OVERLAY)
-      overlay_planes_.push_back(plane.get());
-  }
-}
-
-int DrmComposition::Init(uint64_t frame_no) {
-  for (auto &conn : drm_->connectors()) {
-    int display = conn->display();
-    composition_map_[display].reset(new DrmDisplayComposition());
-    if (!composition_map_[display]) {
-      ALOGE("Failed to allocate new display composition\n");
-      return -ENOMEM;
-    }
-
-    // If the display hasn't been modeset yet, this will be NULL
-    DrmCrtc *crtc = drm_->GetCrtcForDisplay(display);
-
-    int ret = composition_map_[display]->Init(drm_, crtc, importer_, planner_,
-                                              frame_no);
-    if (ret) {
-      ALOGE("Failed to init display composition for %d", display);
-      return ret;
-    }
-  }
-  return 0;
-}
-
-int DrmComposition::SetLayers(size_t num_displays,
-                              DrmCompositionDisplayLayersMap *maps) {
-  int ret = 0;
-  for (size_t display_index = 0; display_index < num_displays;
-       display_index++) {
-    DrmCompositionDisplayLayersMap &map = maps[display_index];
-    int display = map.display;
-
-    if (!drm_->GetConnectorForDisplay(display)) {
-      ALOGE("Invalid display given to SetLayers %d", display);
-      continue;
-    }
-
-    ret = composition_map_[display]->SetLayers(
-        map.layers.data(), map.layers.size(), map.geometry_changed);
-    if (ret)
-      return ret;
-  }
-
-  return 0;
-}
-
-int DrmComposition::SetDpmsMode(int display, uint32_t dpms_mode) {
-  return composition_map_[display]->SetDpmsMode(dpms_mode);
-}
-
-int DrmComposition::SetDisplayMode(int display, const DrmMode &display_mode) {
-  return composition_map_[display]->SetDisplayMode(display_mode);
-}
-
-std::unique_ptr<DrmDisplayComposition> DrmComposition::TakeDisplayComposition(
-    int display) {
-  return std::move(composition_map_[display]);
-}
-
-int DrmComposition::Plan(std::map<int, DrmDisplayCompositor> &compositor_map) {
-  int ret = 0;
-  for (auto &conn : drm_->connectors()) {
-    int display = conn->display();
-    DrmDisplayComposition *comp = GetDisplayComposition(display);
-    ret = comp->Plan(compositor_map[display].squash_state(), &primary_planes_,
-                     &overlay_planes_);
-    if (ret) {
-      ALOGE("Failed to plan composition for dislay %d", display);
-      return ret;
-    }
-  }
-
-  return 0;
-}
-
-int DrmComposition::DisableUnusedPlanes() {
-  for (auto &conn : drm_->connectors()) {
-    int display = conn->display();
-    DrmDisplayComposition *comp = GetDisplayComposition(display);
-
-    /*
-     * Leave empty compositions alone
-     * TODO: re-visit this and potentially disable leftover planes after the
-     *       active compositions have gobbled up all they can
-     */
-    if (comp->type() == DRM_COMPOSITION_TYPE_EMPTY ||
-        comp->type() == DRM_COMPOSITION_TYPE_MODESET)
-      continue;
-
-    DrmCrtc *crtc = drm_->GetCrtcForDisplay(display);
-    if (!crtc) {
-      ALOGE("Failed to find crtc for display %d", display);
-      continue;
-    }
-
-    for (std::vector<DrmPlane *>::iterator iter = primary_planes_.begin();
-         iter != primary_planes_.end(); ++iter) {
-      if ((*iter)->GetCrtcSupported(*crtc)) {
-        comp->AddPlaneDisable(*iter);
-        primary_planes_.erase(iter);
-        break;
-      }
-    }
-    for (std::vector<DrmPlane *>::iterator iter = overlay_planes_.begin();
-         iter != overlay_planes_.end();) {
-      if ((*iter)->GetCrtcSupported(*crtc)) {
-        comp->AddPlaneDisable(*iter);
-        iter = overlay_planes_.erase(iter);
-      } else {
-        iter++;
-      }
-    }
-  }
-  return 0;
-}
-
-DrmDisplayComposition *DrmComposition::GetDisplayComposition(int display) {
-  return composition_map_[display].get();
-}
-}
diff --git a/drmcomposition.h b/drmcomposition.h
deleted file mode 100644
index eae8cde..0000000
--- a/drmcomposition.h
+++ /dev/null
@@ -1,79 +0,0 @@
-/*
- * Copyright (C) 2015 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-#ifndef ANDROID_DRM_COMPOSITION_H_
-#define ANDROID_DRM_COMPOSITION_H_
-
-#include "drmhwcomposer.h"
-#include "drmdisplaycomposition.h"
-#include "drmplane.h"
-#include "platform.h"
-
-#include <map>
-#include <vector>
-
-#include <hardware/hardware.h>
-#include <hardware/hwcomposer.h>
-
-namespace android {
-
-class DrmDisplayCompositor;
-
-struct DrmCompositionDisplayLayersMap {
-  int display;
-  bool geometry_changed = true;
-  std::vector<DrmHwcLayer> layers;
-
-  DrmCompositionDisplayLayersMap() = default;
-  DrmCompositionDisplayLayersMap(DrmCompositionDisplayLayersMap &&rhs) =
-      default;
-};
-
-class DrmComposition {
- public:
-  DrmComposition(DrmResources *drm, Importer *importer, Planner *planner);
-
-  int Init(uint64_t frame_no);
-
-  int SetLayers(size_t num_displays, DrmCompositionDisplayLayersMap *maps);
-  int SetDpmsMode(int display, uint32_t dpms_mode);
-  int SetDisplayMode(int display, const DrmMode &display_mode);
-
-  std::unique_ptr<DrmDisplayComposition> TakeDisplayComposition(int display);
-  DrmDisplayComposition *GetDisplayComposition(int display);
-
-  int Plan(std::map<int, DrmDisplayCompositor> &compositor_map);
-  int DisableUnusedPlanes();
-
- private:
-  DrmComposition(const DrmComposition &) = delete;
-
-  DrmResources *drm_;
-  Importer *importer_;
-  Planner *planner_;
-
-  std::vector<DrmPlane *> primary_planes_;
-  std::vector<DrmPlane *> overlay_planes_;
-
-  /*
-   * This _must_ be read-only after it's passed to QueueComposition. Otherwise
-   * locking is required to maintain consistency across the compositor threads.
-   */
-  std::map<int, std::unique_ptr<DrmDisplayComposition>> composition_map_;
-};
-}
-
-#endif  // ANDROID_DRM_COMPOSITION_H_
diff --git a/drmcompositor.cpp b/drmcompositor.cpp
deleted file mode 100644
index c1f3ed8..0000000
--- a/drmcompositor.cpp
+++ /dev/null
@@ -1,106 +0,0 @@
-/*
- * Copyright (C) 2015 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-#define LOG_TAG "hwc-drm-compositor"
-
-#include "drmcompositor.h"
-#include "drmdisplaycompositor.h"
-#include "drmresources.h"
-#include "platform.h"
-
-#include <sstream>
-#include <stdlib.h>
-
-#include <cutils/log.h>
-
-namespace android {
-
-DrmCompositor::DrmCompositor(DrmResources *drm) : drm_(drm), frame_no_(0) {
-}
-
-DrmCompositor::~DrmCompositor() {
-}
-
-int DrmCompositor::Init() {
-  for (auto &conn : drm_->connectors()) {
-    int display = conn->display();
-    int ret = compositor_map_[display].Init(drm_, display);
-    if (ret) {
-      ALOGE("Failed to initialize display compositor for %d", display);
-      return ret;
-    }
-  }
-  planner_ = Planner::CreateInstance(drm_);
-  if (!planner_) {
-    ALOGE("Failed to create planner instance for composition");
-    return -ENOMEM;
-  }
-
-  return 0;
-}
-
-std::unique_ptr<DrmComposition> DrmCompositor::CreateComposition(
-    Importer *importer) {
-  std::unique_ptr<DrmComposition> composition(
-      new DrmComposition(drm_, importer, planner_.get()));
-  int ret = composition->Init(++frame_no_);
-  if (ret) {
-    ALOGE("Failed to initialize drm composition %d", ret);
-    return nullptr;
-  }
-  return composition;
-}
-
-int DrmCompositor::QueueComposition(
-    std::unique_ptr<DrmComposition> composition) {
-  int ret;
-
-  ret = composition->Plan(compositor_map_);
-  if (ret)
-    return ret;
-
-  ret = composition->DisableUnusedPlanes();
-  if (ret)
-    return ret;
-
-  for (auto &conn : drm_->connectors()) {
-    int display = conn->display();
-    int ret = compositor_map_[display].QueueComposition(
-        composition->TakeDisplayComposition(display));
-    if (ret) {
-      ALOGE("Failed to queue composition for display %d (%d)", display, ret);
-      return ret;
-    }
-  }
-
-  return 0;
-}
-
-int DrmCompositor::Composite() {
-  /*
-   * This shouldn't be called, we should be calling Composite() on the display
-   * compositors directly.
-   */
-  ALOGE("Calling base drm compositor Composite() function");
-  return -EINVAL;
-}
-
-void DrmCompositor::Dump(std::ostringstream *out) const {
-  *out << "DrmCompositor stats:\n";
-  for (auto &conn : drm_->connectors())
-    compositor_map_[conn->display()].Dump(out);
-}
-}
diff --git a/drmcompositor.h b/drmcompositor.h
deleted file mode 100644
index 19271b5..0000000
--- a/drmcompositor.h
+++ /dev/null
@@ -1,56 +0,0 @@
-/*
- * Copyright (C) 2015 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-#ifndef ANDROID_DRM_COMPOSITOR_H_
-#define ANDROID_DRM_COMPOSITOR_H_
-
-#include "drmcomposition.h"
-#include "drmdisplaycompositor.h"
-#include "platform.h"
-
-#include <map>
-#include <memory>
-#include <sstream>
-
-namespace android {
-
-class DrmCompositor {
- public:
-  DrmCompositor(DrmResources *drm);
-  ~DrmCompositor();
-
-  int Init();
-
-  std::unique_ptr<DrmComposition> CreateComposition(Importer *importer);
-
-  int QueueComposition(std::unique_ptr<DrmComposition> composition);
-  int Composite();
-  void Dump(std::ostringstream *out) const;
-
- private:
-  DrmCompositor(const DrmCompositor &) = delete;
-
-  DrmResources *drm_;
-  std::unique_ptr<Planner> planner_;
-
-  uint64_t frame_no_;
-
-  // mutable for Dump() propagation
-  mutable std::map<int, DrmDisplayCompositor> compositor_map_;
-};
-}
-
-#endif  // ANDROID_DRM_COMPOSITOR_H_
diff --git a/drmcompositorworker.cpp b/drmcompositorworker.cpp
deleted file mode 100644
index 9804322..0000000
--- a/drmcompositorworker.cpp
+++ /dev/null
@@ -1,87 +0,0 @@
-/*
- * Copyright (C) 2015 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-#define LOG_TAG "hwc-drm-compositor-worker"
-
-#include "drmdisplaycompositor.h"
-#include "drmcompositorworker.h"
-#include "worker.h"
-
-#include <stdlib.h>
-
-#include <cutils/log.h>
-#include <hardware/hardware.h>
-
-namespace android {
-
-static const int64_t kSquashWait = 500000000LL;
-
-DrmCompositorWorker::DrmCompositorWorker(DrmDisplayCompositor *compositor)
-    : Worker("drm-compositor", HAL_PRIORITY_URGENT_DISPLAY),
-      compositor_(compositor) {
-}
-
-DrmCompositorWorker::~DrmCompositorWorker() {
-}
-
-int DrmCompositorWorker::Init() {
-  return InitWorker();
-}
-
-void DrmCompositorWorker::Routine() {
-  int ret;
-  if (!compositor_->HaveQueuedComposites()) {
-    ret = Lock();
-    if (ret) {
-      ALOGE("Failed to lock worker, %d", ret);
-      return;
-    }
-
-    // Only use a timeout if we didn't do a SquashAll last time. This will
-    // prevent wait_ret == -ETIMEDOUT which would trigger a SquashAll and be a
-    // pointless drain on resources.
-    int wait_ret = did_squash_all_ ? WaitForSignalOrExitLocked()
-                                   : WaitForSignalOrExitLocked(kSquashWait);
-
-    ret = Unlock();
-    if (ret) {
-      ALOGE("Failed to unlock worker, %d", ret);
-      return;
-    }
-
-    switch (wait_ret) {
-      case 0:
-        break;
-      case -EINTR:
-        return;
-      case -ETIMEDOUT:
-        ret = compositor_->SquashAll();
-        if (ret)
-          ALOGE("Failed to squash all %d", ret);
-        did_squash_all_ = true;
-        return;
-      default:
-        ALOGE("Failed to wait for signal, %d", wait_ret);
-        return;
-    }
-  }
-
-  ret = compositor_->Composite();
-  if (ret)
-    ALOGE("Failed to composite! %d", ret);
-  did_squash_all_ = false;
-}
-}
diff --git a/drmcompositorworker.h b/drmcompositorworker.h
deleted file mode 100644
index 731bc65..0000000
--- a/drmcompositorworker.h
+++ /dev/null
@@ -1,41 +0,0 @@
-/*
- * Copyright (C) 2015 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-#ifndef ANDROID_DRM_COMPOSITOR_WORKER_H_
-#define ANDROID_DRM_COMPOSITOR_WORKER_H_
-
-#include "worker.h"
-
-namespace android {
-
-class DrmDisplayCompositor;
-
-class DrmCompositorWorker : public Worker {
- public:
-  DrmCompositorWorker(DrmDisplayCompositor *compositor);
-  ~DrmCompositorWorker() override;
-
-  int Init();
-
- protected:
-  void Routine() override;
-
-  DrmDisplayCompositor *compositor_;
-  bool did_squash_all_ = false;
-};
-}
-
-#endif
diff --git a/drmdisplaycomposition.cpp b/drmdisplaycomposition.cpp
index 293160b..bc1d668 100644
--- a/drmdisplaycomposition.cpp
+++ b/drmdisplaycomposition.cpp
@@ -17,6 +17,7 @@
 #define LOG_TAG "hwc-drm-display-composition"
 
 #include "drmdisplaycomposition.h"
+#include "drmdisplaycompositor.h"
 #include "drmcrtc.h"
 #include "drmplane.h"
 #include "drmresources.h"
diff --git a/drmdisplaycomposition.h b/drmdisplaycomposition.h
index 13da19d..b165adc 100644
--- a/drmdisplaycomposition.h
+++ b/drmdisplaycomposition.h
@@ -42,6 +42,16 @@ enum DrmCompositionType {
   DRM_COMPOSITION_TYPE_MODESET,
 };
 
+struct DrmCompositionDisplayLayersMap {
+  int display;
+  bool geometry_changed = true;
+  std::vector<DrmHwcLayer> layers;
+
+  DrmCompositionDisplayLayersMap() = default;
+  DrmCompositionDisplayLayersMap(DrmCompositionDisplayLayersMap &&rhs) =
+      default;
+};
+
 struct DrmCompositionRegion {
   DrmHwcRect<int> frame;
   std::vector<size_t> source_layers;
diff --git a/drmdisplaycompositor.cpp b/drmdisplaycompositor.cpp
index bc0adbc..bd670cf 100644
--- a/drmdisplaycompositor.cpp
+++ b/drmdisplaycompositor.cpp
@@ -37,8 +37,6 @@
 #include "drmresources.h"
 #include "glworker.h"
 
-#define DRM_DISPLAY_COMPOSITOR_MAX_QUEUE_DEPTH 2
-
 namespace android {
 
 void SquashState::Init(DrmHwcLayer *layers, size_t num_layers) {
@@ -176,67 +174,9 @@ static bool UsesSquash(const std::vector<DrmCompositionPlane> &comp_planes) {
   });
 }
 
-DrmDisplayCompositor::FrameWorker::FrameWorker(DrmDisplayCompositor *compositor)
-    : Worker("frame-worker", HAL_PRIORITY_URGENT_DISPLAY),
-      compositor_(compositor) {
-}
-
-DrmDisplayCompositor::FrameWorker::~FrameWorker() {
-}
-
-int DrmDisplayCompositor::FrameWorker::Init() {
-  return InitWorker();
-}
-
-void DrmDisplayCompositor::FrameWorker::QueueFrame(
-    std::unique_ptr<DrmDisplayComposition> composition, int status) {
-  Lock();
-  FrameState frame;
-  frame.composition = std::move(composition);
-  frame.status = status;
-  frame_queue_.push(std::move(frame));
-  SignalLocked();
-  Unlock();
-}
-
-void DrmDisplayCompositor::FrameWorker::Routine() {
-  int ret = Lock();
-  if (ret) {
-    ALOGE("Failed to lock worker, %d", ret);
-    return;
-  }
-
-  int wait_ret = 0;
-  if (frame_queue_.empty()) {
-    wait_ret = WaitForSignalOrExitLocked();
-  }
-
-  FrameState frame;
-  if (!frame_queue_.empty()) {
-    frame = std::move(frame_queue_.front());
-    frame_queue_.pop();
-  }
-
-  ret = Unlock();
-  if (ret) {
-    ALOGE("Failed to unlock worker, %d", ret);
-    return;
-  }
-
-  if (wait_ret == -EINTR) {
-    return;
-  } else if (wait_ret) {
-    ALOGE("Failed to wait for signal, %d", wait_ret);
-    return;
-  }
-  compositor_->ApplyFrame(std::move(frame.composition), frame.status);
-}
-
 DrmDisplayCompositor::DrmDisplayCompositor()
     : drm_(NULL),
       display_(-1),
-      worker_(this),
-      frame_worker_(this),
       initialized_(false),
       active_(false),
       use_hw_overlays_(true),
@@ -254,9 +194,6 @@ DrmDisplayCompositor::~DrmDisplayCompositor() {
   if (!initialized_)
     return;
 
-  worker_.Exit();
-  frame_worker_.Exit();
-
   int ret = pthread_mutex_lock(&lock_);
   if (ret)
     ALOGE("Failed to acquire compositor lock %d", ret);
@@ -266,10 +203,6 @@ DrmDisplayCompositor::~DrmDisplayCompositor() {
   if (mode_.old_blob_id)
     drm_->DestroyPropertyBlob(mode_.old_blob_id);
 
-  while (!composite_queue_.empty()) {
-    composite_queue_.front().reset();
-    composite_queue_.pop();
-  }
   active_composition_.reset();
 
   ret = pthread_mutex_unlock(&lock_);
@@ -288,18 +221,6 @@ int DrmDisplayCompositor::Init(DrmResources *drm, int display) {
     ALOGE("Failed to initialize drm compositor lock %d\n", ret);
     return ret;
   }
-  ret = worker_.Init();
-  if (ret) {
-    pthread_mutex_destroy(&lock_);
-    ALOGE("Failed to initialize compositor worker %d\n", ret);
-    return ret;
-  }
-  ret = frame_worker_.Init();
-  if (ret) {
-    pthread_mutex_destroy(&lock_);
-    ALOGE("Failed to initialize frame worker %d\n", ret);
-    return ret;
-  }
 
   initialized_ = true;
   return 0;
@@ -310,55 +231,6 @@ std::unique_ptr<DrmDisplayComposition> DrmDisplayCompositor::CreateComposition()
   return std::unique_ptr<DrmDisplayComposition>(new DrmDisplayComposition());
 }
 
-int DrmDisplayCompositor::QueueComposition(
-    std::unique_ptr<DrmDisplayComposition> composition) {
-  switch (composition->type()) {
-    case DRM_COMPOSITION_TYPE_FRAME:
-      if (!active_)
-        return -ENODEV;
-      break;
-    case DRM_COMPOSITION_TYPE_DPMS:
-      /*
-       * Update the state as soon as we get it so we can start/stop queuing
-       * frames asap.
-       */
-      active_ = (composition->dpms_mode() == DRM_MODE_DPMS_ON);
-      break;
-    case DRM_COMPOSITION_TYPE_MODESET:
-      break;
-    case DRM_COMPOSITION_TYPE_EMPTY:
-      return 0;
-    default:
-      ALOGE("Unknown composition type %d/%d", composition->type(), display_);
-      return -ENOENT;
-  }
-
-  int ret = pthread_mutex_lock(&lock_);
-  if (ret) {
-    ALOGE("Failed to acquire compositor lock %d", ret);
-    return ret;
-  }
-
-  // Block the queue if it gets too large. Otherwise, SurfaceFlinger will start
-  // to eat our buffer handles when we get about 1 second behind.
-  while (composite_queue_.size() >= DRM_DISPLAY_COMPOSITOR_MAX_QUEUE_DEPTH) {
-    pthread_mutex_unlock(&lock_);
-    sched_yield();
-    pthread_mutex_lock(&lock_);
-  }
-
-  composite_queue_.push(std::move(composition));
-
-  ret = pthread_mutex_unlock(&lock_);
-  if (ret) {
-    ALOGE("Failed to release compositor lock %d", ret);
-    return ret;
-  }
-
-  worker_.Signal();
-  return 0;
-}
-
 std::tuple<uint32_t, uint32_t, int>
 DrmDisplayCompositor::GetActiveModeResolution() {
   DrmConnector *connector = drm_->GetConnectorForDisplay(display_);
@@ -523,6 +395,15 @@ int DrmDisplayCompositor::PrepareFrame(DrmDisplayComposition *display_comp) {
   std::vector<DrmCompositionRegion> &pre_comp_regions =
       display_comp->pre_comp_regions();
 
+  if (!pre_compositor_) {
+    pre_compositor_.reset(new GLWorkerCompositor());
+    int ret = pre_compositor_->Init();
+    if (ret) {
+      ALOGE("Failed to initialize OpenGL compositor %d", ret);
+      return ret;
+    }
+  }
+
   int squash_layer_index = -1;
   if (squash_regions.size() > 0) {
     squash_framebuffer_index_ = (squash_framebuffer_index_ + 1) % 2;
@@ -915,41 +796,9 @@ void DrmDisplayCompositor::ApplyFrame(
     ALOGE("Failed to release lock for active_composition swap");
 }
 
-int DrmDisplayCompositor::Composite() {
-  ATRACE_CALL();
-
-  if (!pre_compositor_) {
-    pre_compositor_.reset(new GLWorkerCompositor());
-    int ret = pre_compositor_->Init();
-    if (ret) {
-      ALOGE("Failed to initialize OpenGL compositor %d", ret);
-      return ret;
-    }
-  }
-
-  int ret = pthread_mutex_lock(&lock_);
-  if (ret) {
-    ALOGE("Failed to acquire compositor lock %d", ret);
-    return ret;
-  }
-  if (composite_queue_.empty()) {
-    ret = pthread_mutex_unlock(&lock_);
-    if (ret)
-      ALOGE("Failed to release compositor lock %d", ret);
-    return ret;
-  }
-
-  std::unique_ptr<DrmDisplayComposition> composition(
-      std::move(composite_queue_.front()));
-
-  composite_queue_.pop();
-
-  ret = pthread_mutex_unlock(&lock_);
-  if (ret) {
-    ALOGE("Failed to release compositor lock %d", ret);
-    return ret;
-  }
-
+int DrmDisplayCompositor::ApplyComposition(
+    std::unique_ptr<DrmDisplayComposition> composition) {
+  int ret = 0;
   switch (composition->type()) {
     case DRM_COMPOSITION_TYPE_FRAME:
       ret = PrepareFrame(composition.get());
@@ -968,7 +817,7 @@ int DrmDisplayCompositor::Composite() {
       }
 
       // If use_hw_overlays_ is false, we can't use hardware to composite the
-      // frame. So squash all layers into a single composition and queue that
+      // frame. So squash all layers into a single composition and apply that
       // instead.
       if (!use_hw_overlays_) {
         std::unique_ptr<DrmDisplayComposition> squashed = CreateComposition();
@@ -984,9 +833,10 @@ int DrmDisplayCompositor::Composite() {
           return ret;
         }
       }
-      frame_worker_.QueueFrame(std::move(composition), ret);
+      ApplyFrame(std::move(composition), ret);
       break;
     case DRM_COMPOSITION_TYPE_DPMS:
+      active_ = (composition->dpms_mode() == DRM_MODE_DPMS_ON);
       ret = ApplyDpms(composition.get());
       if (ret)
         ALOGE("Failed to apply dpms for display %d", display_);
@@ -1010,24 +860,6 @@ int DrmDisplayCompositor::Composite() {
   return ret;
 }
 
-bool DrmDisplayCompositor::HaveQueuedComposites() const {
-  int ret = pthread_mutex_lock(&lock_);
-  if (ret) {
-    ALOGE("Failed to acquire compositor lock %d", ret);
-    return false;
-  }
-
-  bool empty_ret = !composite_queue_.empty();
-
-  ret = pthread_mutex_unlock(&lock_);
-  if (ret) {
-    ALOGE("Failed to release compositor lock %d", ret);
-    return false;
-  }
-
-  return empty_ret;
-}
-
 int DrmDisplayCompositor::SquashAll() {
   AutoLock lock(&lock_, "compositor");
   int ret = lock.Lock();
diff --git a/drmdisplaycompositor.h b/drmdisplaycompositor.h
index 9487cac..f1965fb 100644
--- a/drmdisplaycompositor.h
+++ b/drmdisplaycompositor.h
@@ -18,14 +18,12 @@
 #define ANDROID_DRM_DISPLAY_COMPOSITOR_H_
 
 #include "drmhwcomposer.h"
-#include "drmcomposition.h"
-#include "drmcompositorworker.h"
+#include "drmdisplaycomposition.h"
 #include "drmframebuffer.h"
 #include "separate_rects.h"
 
 #include <pthread.h>
 #include <memory>
-#include <queue>
 #include <sstream>
 #include <tuple>
 
@@ -89,42 +87,18 @@ class DrmDisplayCompositor {
   int Init(DrmResources *drm, int display);
 
   std::unique_ptr<DrmDisplayComposition> CreateComposition() const;
-  int QueueComposition(std::unique_ptr<DrmDisplayComposition> composition);
+  int ApplyComposition(std::unique_ptr<DrmDisplayComposition> composition);
   int Composite();
   int SquashAll();
   void Dump(std::ostringstream *out) const;
 
   std::tuple<uint32_t, uint32_t, int> GetActiveModeResolution();
 
-  bool HaveQueuedComposites() const;
-
   SquashState *squash_state() {
     return &squash_state_;
   }
 
  private:
-  struct FrameState {
-    std::unique_ptr<DrmDisplayComposition> composition;
-    int status = 0;
-  };
-
-  class FrameWorker : public Worker {
-   public:
-    FrameWorker(DrmDisplayCompositor *compositor);
-    ~FrameWorker() override;
-
-    int Init();
-    void QueueFrame(std::unique_ptr<DrmDisplayComposition> composition,
-                    int status);
-
-   protected:
-    void Routine() override;
-
-   private:
-    DrmDisplayCompositor *compositor_;
-    std::queue<FrameState> frame_queue_;
-  };
-
   struct ModeState {
     bool needs_modeset = false;
     DrmMode mode;
@@ -158,10 +132,6 @@ class DrmDisplayCompositor {
   DrmResources *drm_;
   int display_;
 
-  DrmCompositorWorker worker_;
-  FrameWorker frame_worker_;
-
-  std::queue<std::unique_ptr<DrmDisplayComposition>> composite_queue_;
   std::unique_ptr<DrmDisplayComposition> active_composition_;
 
   bool initialized_;
@@ -178,7 +148,7 @@ class DrmDisplayCompositor {
   int squash_framebuffer_index_;
   DrmFramebuffer squash_framebuffers_[2];
 
-  // mutable since we need to acquire in HaveQueuedComposites
+  // mutable since we need to acquire in Dump()
   mutable pthread_mutex_t lock_;
 
   // State tracking progress since our last Dump(). These are mutable since
diff --git a/drmeventlistener.cpp b/drmeventlistener.cpp
index 1880549..049ace2 100644
--- a/drmeventlistener.cpp
+++ b/drmeventlistener.cpp
@@ -20,10 +20,13 @@
 #include "drmresources.h"
 
 #include <assert.h>
+#include <errno.h>
 #include <linux/netlink.h>
 #include <sys/socket.h>
 
 #include <cutils/log.h>
+#include <hardware/hardware.h>
+#include <hardware/hwcomposer.h>
 #include <xf86drm.h>
 
 namespace android {
diff --git a/drmresources.cpp b/drmresources.cpp
index 6b8ed03..762f5ef 100644
--- a/drmresources.cpp
+++ b/drmresources.cpp
@@ -35,7 +35,7 @@
 
 namespace android {
 
-DrmResources::DrmResources() : compositor_(this), event_listener_(this) {
+DrmResources::DrmResources() : event_listener_(this) {
 }
 
 DrmResources::~DrmResources() {
@@ -201,10 +201,6 @@ int DrmResources::Init() {
   if (ret)
     return ret;
 
-  ret = compositor_.Init();
-  if (ret)
-    return ret;
-
   ret = event_listener_.Init();
   if (ret) {
     ALOGE("Can't initialize event listener %d", ret);
@@ -333,54 +329,6 @@ int DrmResources::DestroyPropertyBlob(uint32_t blob_id) {
   return 0;
 }
 
-int DrmResources::SetDisplayActiveMode(int display, const DrmMode &mode) {
-  std::unique_ptr<DrmComposition> comp(compositor_.CreateComposition(NULL));
-  if (!comp) {
-    ALOGE("Failed to create composition for dpms on %d", display);
-    return -ENOMEM;
-  }
-  int ret = comp->SetDisplayMode(display, mode);
-  if (ret) {
-    ALOGE("Failed to add mode to composition on %d %d", display, ret);
-    return ret;
-  }
-  ret = compositor_.QueueComposition(std::move(comp));
-  if (ret) {
-    ALOGE("Failed to queue dpms composition on %d %d", display, ret);
-    return ret;
-  }
-  return 0;
-}
-
-int DrmResources::SetDpmsMode(int display, uint64_t mode) {
-  if (mode != DRM_MODE_DPMS_ON && mode != DRM_MODE_DPMS_OFF) {
-    ALOGE("Invalid dpms mode %" PRIu64, mode);
-    return -EINVAL;
-  }
-
-  std::unique_ptr<DrmComposition> comp(compositor_.CreateComposition(NULL));
-  if (!comp) {
-    ALOGE("Failed to create composition for dpms on %d", display);
-    return -ENOMEM;
-  }
-  int ret = comp->SetDpmsMode(display, mode);
-  if (ret) {
-    ALOGE("Failed to add dpms %" PRIu64 " to composition on %d %d", mode,
-          display, ret);
-    return ret;
-  }
-  ret = compositor_.QueueComposition(std::move(comp));
-  if (ret) {
-    ALOGE("Failed to queue dpms composition on %d %d", display, ret);
-    return ret;
-  }
-  return 0;
-}
-
-DrmCompositor *DrmResources::compositor() {
-  return &compositor_;
-}
-
 DrmEventListener *DrmResources::event_listener() {
   return &event_listener_;
 }
diff --git a/drmresources.h b/drmresources.h
index 011f87e..a2d8d16 100644
--- a/drmresources.h
+++ b/drmresources.h
@@ -17,7 +17,6 @@
 #ifndef ANDROID_DRM_H_
 #define ANDROID_DRM_H_
 
-#include "drmcompositor.h"
 #include "drmconnector.h"
 #include "drmcrtc.h"
 #include "drmencoder.h"
@@ -58,7 +57,6 @@ class DrmResources {
   DrmConnector *GetConnectorForDisplay(int display) const;
   DrmCrtc *GetCrtcForDisplay(int display) const;
   DrmPlane *GetPlane(uint32_t id) const;
-  DrmCompositor *compositor();
   DrmEventListener *event_listener();
 
   int GetPlaneProperty(const DrmPlane &plane, const char *prop_name,
@@ -69,8 +67,6 @@ class DrmResources {
                            DrmProperty *property);
 
   uint32_t next_mode_id();
-  int SetDisplayActiveMode(int display, const DrmMode &mode);
-  int SetDpmsMode(int display, uint64_t mode);
 
   int CreatePropertyBlob(void *data, size_t length, uint32_t *blob_id);
   int DestroyPropertyBlob(uint32_t blob_id);
@@ -89,7 +85,6 @@ class DrmResources {
   std::vector<std::unique_ptr<DrmEncoder>> encoders_;
   std::vector<std::unique_ptr<DrmCrtc>> crtcs_;
   std::vector<std::unique_ptr<DrmPlane>> planes_;
-  DrmCompositor compositor_;
   DrmEventListener event_listener_;
 
   std::pair<uint32_t, uint32_t> min_resolution_;
diff --git a/glworker.cpp b/glworker.cpp
index e12995e..e90576a 100644
--- a/glworker.cpp
+++ b/glworker.cpp
@@ -143,6 +143,38 @@ static bool HasExtension(const char *extension, const char *extensions) {
   return false;
 }
 
+int GLWorkerCompositor::BeginContext() {
+  private_.saved_egl_display = eglGetCurrentDisplay();
+  private_.saved_egl_ctx = eglGetCurrentContext();
+
+  if (private_.saved_egl_display != egl_display_ ||
+      private_.saved_egl_ctx != egl_ctx_) {
+    private_.saved_egl_read = eglGetCurrentSurface(EGL_READ);
+    private_.saved_egl_draw = eglGetCurrentSurface(EGL_DRAW);
+  } else {
+    return 0;
+  }
+
+  if (!eglMakeCurrent(egl_display_, EGL_NO_SURFACE, EGL_NO_SURFACE, egl_ctx_)) {
+    ALOGE("BeginContext failed: %s", GetEGLError());
+    return 1;
+  }
+  return 0;
+}
+
+int GLWorkerCompositor::EndContext() {
+  if (private_.saved_egl_display != eglGetCurrentDisplay() ||
+      private_.saved_egl_ctx != eglGetCurrentContext()) {
+    if (!eglMakeCurrent(private_.saved_egl_display, private_.saved_egl_read,
+                        private_.saved_egl_draw, private_.saved_egl_ctx)) {
+      ALOGE("EndContext failed: %s", GetEGLError());
+      return 1;
+    }
+  }
+
+  return 0;
+}
+
 static AutoGLShader CompileAndCheckShader(GLenum type, unsigned source_count,
                                           const GLchar **sources,
                                           std::ostringstream *shader_log) {
@@ -508,10 +540,9 @@ int GLWorkerCompositor::Init() {
     return 1;
   }
 
-  if (!eglMakeCurrent(egl_display_, EGL_NO_SURFACE, EGL_NO_SURFACE, egl_ctx_)) {
-    ALOGE("Failed to make the OpenGL ES Context current: %s", GetEGLError());
-    return 1;
-  }
+  ret = BeginContext();
+  if (ret)
+    return ret;
 
   gl_extensions = (const char *)glGetString(GL_EXTENSIONS);
 
@@ -530,6 +561,9 @@ int GLWorkerCompositor::Init() {
 
   std::ostringstream shader_log;
   blend_programs_.emplace_back(GenerateProgram(1, &shader_log));
+
+  EndContext();
+
   if (blend_programs_.back().get() == 0) {
     ALOGE("%s", shader_log.str().c_str());
     return 1;
@@ -558,12 +592,17 @@ int GLWorkerCompositor::Composite(DrmHwcLayer *layers,
     return -EALREADY;
   }
 
+  ret = BeginContext();
+  if (ret)
+    return -1;
+
   GLint frame_width = framebuffer->getWidth();
   GLint frame_height = framebuffer->getHeight();
   CachedFramebuffer *cached_framebuffer =
       PrepareAndCacheFramebuffer(framebuffer);
   if (cached_framebuffer == NULL) {
     ALOGE("Composite failed because of failed framebuffer");
+    EndContext();
     return -EINVAL;
   }
 
@@ -597,8 +636,10 @@ int GLWorkerCompositor::Composite(DrmHwcLayer *layers,
     }
   }
 
-  if (ret)
+  if (ret) {
+    EndContext();
     return ret;
+  }
 
   glViewport(0, 0, frame_width, frame_height);
 
@@ -676,6 +717,7 @@ int GLWorkerCompositor::Composite(DrmHwcLayer *layers,
 
   glBindFramebuffer(GL_FRAMEBUFFER, 0);
 
+  EndContext();
   return ret;
 }
 
diff --git a/glworker.h b/glworker.h
index 158490c..26de55d 100644
--- a/glworker.h
+++ b/glworker.h
@@ -64,6 +64,16 @@ class GLWorkerCompositor {
     bool Promote();
   };
 
+  struct {
+    EGLDisplay saved_egl_display = EGL_NO_DISPLAY;
+    EGLContext saved_egl_ctx = EGL_NO_CONTEXT;
+    EGLSurface saved_egl_read = EGL_NO_SURFACE;
+    EGLSurface saved_egl_draw = EGL_NO_SURFACE;
+  } private_;
+
+  int BeginContext();
+  int EndContext();
+
   CachedFramebuffer *FindCachedFramebuffer(
       const sp<GraphicBuffer> &framebuffer);
   CachedFramebuffer *PrepareAndCacheFramebuffer(
diff --git a/hwcomposer.cpp b/hwcomposer.cpp
deleted file mode 100644
index e0483e9..0000000
--- a/hwcomposer.cpp
+++ /dev/null
@@ -1,840 +0,0 @@
-/*
- * Copyright (C) 2015 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-#define ATRACE_TAG ATRACE_TAG_GRAPHICS
-#define LOG_TAG "hwcomposer-drm"
-
-#include "drmhwcomposer.h"
-#include "drmeventlistener.h"
-#include "drmresources.h"
-#include "platform.h"
-#include "virtualcompositorworker.h"
-#include "vsyncworker.h"
-
-#include <stdlib.h>
-
-#include <cinttypes>
-#include <map>
-#include <vector>
-#include <sstream>
-
-#include <errno.h>
-#include <fcntl.h>
-#include <pthread.h>
-#include <sys/param.h>
-#include <sys/resource.h>
-#include <xf86drm.h>
-#include <xf86drmMode.h>
-
-#include <cutils/log.h>
-#include <cutils/properties.h>
-#include <hardware/hardware.h>
-#include <hardware/hwcomposer.h>
-#include <sw_sync.h>
-#include <sync/sync.h>
-#include <utils/Trace.h>
-
-#define UM_PER_INCH 25400
-
-namespace android {
-
-class DummySwSyncTimeline {
- public:
-  int Init() {
-    int ret = timeline_fd_.Set(sw_sync_timeline_create());
-    if (ret < 0)
-      return ret;
-    return 0;
-  }
-
-  UniqueFd CreateDummyFence() {
-    int ret = sw_sync_fence_create(timeline_fd_.get(), "dummy fence",
-                                   timeline_pt_ + 1);
-    if (ret < 0) {
-      ALOGE("Failed to create dummy fence %d", ret);
-      return ret;
-    }
-
-    UniqueFd ret_fd(ret);
-
-    ret = sw_sync_timeline_inc(timeline_fd_.get(), 1);
-    if (ret) {
-      ALOGE("Failed to increment dummy sync timeline %d", ret);
-      return ret;
-    }
-
-    ++timeline_pt_;
-    return ret_fd;
-  }
-
- private:
-  UniqueFd timeline_fd_;
-  int timeline_pt_ = 0;
-};
-
-struct CheckedOutputFd {
-  CheckedOutputFd(int *fd, const char *description,
-                  DummySwSyncTimeline &timeline)
-      : fd_(fd), description_(description), timeline_(timeline) {
-  }
-  CheckedOutputFd(CheckedOutputFd &&rhs)
-      : description_(rhs.description_), timeline_(rhs.timeline_) {
-    std::swap(fd_, rhs.fd_);
-  }
-
-  CheckedOutputFd &operator=(const CheckedOutputFd &rhs) = delete;
-
-  ~CheckedOutputFd() {
-    if (fd_ == NULL)
-      return;
-
-    if (*fd_ >= 0)
-      return;
-
-    *fd_ = timeline_.CreateDummyFence().Release();
-
-    if (*fd_ < 0)
-      ALOGE("Failed to fill %s (%p == %d) before destruction",
-            description_.c_str(), fd_, *fd_);
-  }
-
- private:
-  int *fd_ = NULL;
-  std::string description_;
-  DummySwSyncTimeline &timeline_;
-};
-
-typedef struct hwc_drm_display {
-  struct hwc_context_t *ctx;
-  int display;
-
-  std::vector<uint32_t> config_ids;
-
-  VSyncWorker vsync_worker;
-} hwc_drm_display_t;
-
-class DrmHotplugHandler : public DrmEventHandler {
- public:
-  void Init(DrmResources *drm, const struct hwc_procs *procs) {
-    drm_ = drm;
-    procs_ = procs;
-  }
-
-  void HandleEvent(uint64_t timestamp_us) {
-    for (auto &conn : drm_->connectors()) {
-      drmModeConnection old_state = conn->state();
-
-      conn->UpdateModes();
-
-      drmModeConnection cur_state = conn->state();
-
-      if (cur_state == old_state)
-        continue;
-
-      ALOGI("%s event @%" PRIu64 " for connector %u\n",
-            cur_state == DRM_MODE_CONNECTED ? "Plug" : "Unplug", timestamp_us,
-            conn->id());
-
-      if (cur_state == DRM_MODE_CONNECTED) {
-        // Take the first one, then look for the preferred
-        DrmMode mode = *(conn->modes().begin());
-        for (auto &m : conn->modes()) {
-          if (m.type() & DRM_MODE_TYPE_PREFERRED) {
-            mode = m;
-            break;
-          }
-        }
-        ALOGI("Setting mode %dx%d for connector %d\n", mode.h_display(),
-              mode.v_display(), conn->id());
-        int ret = drm_->SetDisplayActiveMode(conn->display(), mode);
-        if (ret) {
-          ALOGE("Failed to set active config %d", ret);
-          return;
-        }
-      } else {
-        int ret = drm_->SetDpmsMode(conn->display(), DRM_MODE_DPMS_OFF);
-        if (ret) {
-          ALOGE("Failed to set dpms mode off %d", ret);
-          return;
-        }
-      }
-
-      procs_->hotplug(procs_, conn->display(),
-                      cur_state == DRM_MODE_CONNECTED ? 1 : 0);
-    }
-  }
-
- private:
-  DrmResources *drm_ = NULL;
-  const struct hwc_procs *procs_ = NULL;
-};
-
-struct hwc_context_t {
-  // map of display:hwc_drm_display_t
-  typedef std::map<int, hwc_drm_display_t> DisplayMap;
-
-  ~hwc_context_t() {
-    virtual_compositor_worker.Exit();
-  }
-
-  hwc_composer_device_1_t device;
-  hwc_procs_t const *procs = NULL;
-
-  DisplayMap displays;
-  DrmResources drm;
-  std::unique_ptr<Importer> importer;
-  const gralloc_module_t *gralloc;
-  DummySwSyncTimeline dummy_timeline;
-  VirtualCompositorWorker virtual_compositor_worker;
-  DrmHotplugHandler hotplug_handler;
-};
-
-class DrmVsyncCallback : public VsyncCallback {
- public:
-  DrmVsyncCallback(hwc_procs_t const *procs) : procs_(procs) {
-  }
-
-  void Callback(int display, int64_t timestamp) {
-    procs_->vsync(procs_, display, timestamp);
-  }
- private:
-  hwc_procs_t const *procs_;
-};
-
-static void hwc_dump(struct hwc_composer_device_1 *dev, char *buff,
-                     int buff_len) {
-  struct hwc_context_t *ctx = (struct hwc_context_t *)&dev->common;
-  std::ostringstream out;
-
-  ctx->drm.compositor()->Dump(&out);
-  std::string out_str = out.str();
-  strncpy(buff, out_str.c_str(),
-          std::min((size_t)buff_len, out_str.length() + 1));
-  buff[buff_len - 1] = '\0';
-}
-
-static bool hwc_skip_layer(const std::pair<int, int> &indices, int i) {
-  return indices.first >= 0 && i >= indices.first && i <= indices.second;
-}
-
-static int hwc_prepare(hwc_composer_device_1_t *dev, size_t num_displays,
-                       hwc_display_contents_1_t **display_contents) {
-  struct hwc_context_t *ctx = (struct hwc_context_t *)&dev->common;
-
-  for (int i = 0; i < (int)num_displays; ++i) {
-    if (!display_contents[i])
-      continue;
-
-    bool use_framebuffer_target = false;
-    DrmMode mode;
-    if (i == HWC_DISPLAY_VIRTUAL) {
-      use_framebuffer_target = true;
-    } else {
-      DrmConnector *c = ctx->drm.GetConnectorForDisplay(i);
-      if (!c) {
-        ALOGE("Failed to get DrmConnector for display %d", i);
-        return -ENODEV;
-      }
-      mode = c->active_mode();
-    }
-
-    // Since we can't composite HWC_SKIP_LAYERs by ourselves, we'll let SF
-    // handle all layers in between the first and last skip layers. So find the
-    // outer indices and mark everything in between as HWC_FRAMEBUFFER
-    std::pair<int, int> skip_layer_indices(-1, -1);
-    int num_layers = display_contents[i]->numHwLayers;
-    for (int j = 0; !use_framebuffer_target && j < num_layers; ++j) {
-      hwc_layer_1_t *layer = &display_contents[i]->hwLayers[j];
-
-      if (!(layer->flags & HWC_SKIP_LAYER))
-        continue;
-
-      if (skip_layer_indices.first == -1)
-        skip_layer_indices.first = j;
-      skip_layer_indices.second = j;
-    }
-
-    for (int j = 0; j < num_layers; ++j) {
-      hwc_layer_1_t *layer = &display_contents[i]->hwLayers[j];
-
-      if (!use_framebuffer_target && !hwc_skip_layer(skip_layer_indices, j)) {
-        // If the layer is off the screen, don't earmark it for an overlay.
-        // We'll leave it as-is, which effectively just drops it from the frame
-        const hwc_rect_t *frame = &layer->displayFrame;
-        if ((frame->right - frame->left) <= 0 ||
-            (frame->bottom - frame->top) <= 0 ||
-            frame->right <= 0 || frame->bottom <= 0 ||
-            frame->left >= (int)mode.h_display() ||
-            frame->top >= (int)mode.v_display())
-            continue;
-
-        if (layer->compositionType == HWC_FRAMEBUFFER)
-          layer->compositionType = HWC_OVERLAY;
-      } else {
-        switch (layer->compositionType) {
-          case HWC_OVERLAY:
-          case HWC_BACKGROUND:
-          case HWC_SIDEBAND:
-          case HWC_CURSOR_OVERLAY:
-            layer->compositionType = HWC_FRAMEBUFFER;
-            break;
-        }
-      }
-    }
-  }
-
-  return 0;
-}
-
-static void hwc_add_layer_to_retire_fence(
-    hwc_layer_1_t *layer, hwc_display_contents_1_t *display_contents) {
-  if (layer->releaseFenceFd < 0)
-    return;
-
-  if (display_contents->retireFenceFd >= 0) {
-    int old_retire_fence = display_contents->retireFenceFd;
-    display_contents->retireFenceFd =
-        sync_merge("dc_retire", old_retire_fence, layer->releaseFenceFd);
-    close(old_retire_fence);
-  } else {
-    display_contents->retireFenceFd = dup(layer->releaseFenceFd);
-  }
-}
-
-static int hwc_set(hwc_composer_device_1_t *dev, size_t num_displays,
-                   hwc_display_contents_1_t **sf_display_contents) {
-  ATRACE_CALL();
-  struct hwc_context_t *ctx = (struct hwc_context_t *)&dev->common;
-  int ret = 0;
-
-  std::vector<CheckedOutputFd> checked_output_fences;
-  std::vector<DrmHwcDisplayContents> displays_contents;
-  std::vector<DrmCompositionDisplayLayersMap> layers_map;
-  std::vector<std::vector<size_t>> layers_indices;
-  displays_contents.reserve(num_displays);
-  // layers_map.reserve(num_displays);
-  layers_indices.reserve(num_displays);
-
-  // Phase one does nothing that would cause errors. Only take ownership of FDs.
-  for (size_t i = 0; i < num_displays; ++i) {
-    hwc_display_contents_1_t *dc = sf_display_contents[i];
-    displays_contents.emplace_back();
-    DrmHwcDisplayContents &display_contents = displays_contents.back();
-    layers_indices.emplace_back();
-    std::vector<size_t> &indices_to_composite = layers_indices.back();
-
-    if (!sf_display_contents[i])
-      continue;
-
-    if (i == HWC_DISPLAY_VIRTUAL) {
-      ctx->virtual_compositor_worker.QueueComposite(dc);
-      continue;
-    }
-
-    std::ostringstream display_index_formatter;
-    display_index_formatter << "retire fence for display " << i;
-    std::string display_fence_description(display_index_formatter.str());
-    checked_output_fences.emplace_back(&dc->retireFenceFd,
-                                       display_fence_description.c_str(),
-                                       ctx->dummy_timeline);
-    display_contents.retire_fence = OutputFd(&dc->retireFenceFd);
-
-    size_t num_dc_layers = dc->numHwLayers;
-    int framebuffer_target_index = -1;
-    for (size_t j = 0; j < num_dc_layers; ++j) {
-      hwc_layer_1_t *sf_layer = &dc->hwLayers[j];
-      if (sf_layer->compositionType == HWC_FRAMEBUFFER_TARGET) {
-        framebuffer_target_index = j;
-        break;
-      }
-    }
-
-    for (size_t j = 0; j < num_dc_layers; ++j) {
-      hwc_layer_1_t *sf_layer = &dc->hwLayers[j];
-
-      display_contents.layers.emplace_back();
-      DrmHwcLayer &layer = display_contents.layers.back();
-
-      // In prepare() we marked all layers FRAMEBUFFER between SKIP_LAYER's.
-      // This means we should insert the FB_TARGET layer in the composition
-      // stack at the location of the first skip layer, and ignore the rest.
-      if (sf_layer->flags & HWC_SKIP_LAYER) {
-        if (framebuffer_target_index < 0)
-          continue;
-        int idx = framebuffer_target_index;
-        framebuffer_target_index = -1;
-        hwc_layer_1_t *fbt_layer = &dc->hwLayers[idx];
-        if (!fbt_layer->handle || (fbt_layer->flags & HWC_SKIP_LAYER)) {
-          ALOGE("Invalid HWC_FRAMEBUFFER_TARGET with HWC_SKIP_LAYER present");
-          continue;
-        }
-        indices_to_composite.push_back(idx);
-        continue;
-      }
-
-      if (sf_layer->compositionType == HWC_OVERLAY)
-        indices_to_composite.push_back(j);
-
-      layer.acquire_fence.Set(sf_layer->acquireFenceFd);
-      sf_layer->acquireFenceFd = -1;
-
-      std::ostringstream layer_fence_formatter;
-      layer_fence_formatter << "release fence for layer " << j << " of display "
-                            << i;
-      std::string layer_fence_description(layer_fence_formatter.str());
-      checked_output_fences.emplace_back(&sf_layer->releaseFenceFd,
-                                         layer_fence_description.c_str(),
-                                         ctx->dummy_timeline);
-      layer.release_fence = OutputFd(&sf_layer->releaseFenceFd);
-    }
-
-    // This is a catch-all in case we get a frame without any overlay layers, or
-    // skip layers, but with a value fb_target layer. This _shouldn't_ happen,
-    // but it's not ruled out by the hwc specification
-    if (indices_to_composite.empty() && framebuffer_target_index >= 0) {
-      hwc_layer_1_t *sf_layer = &dc->hwLayers[framebuffer_target_index];
-      if (!sf_layer->handle || (sf_layer->flags & HWC_SKIP_LAYER)) {
-        ALOGE(
-            "Expected valid layer with HWC_FRAMEBUFFER_TARGET when all "
-            "HWC_OVERLAY layers are skipped.");
-        ret = -EINVAL;
-      }
-      indices_to_composite.push_back(framebuffer_target_index);
-    }
-  }
-
-  if (ret)
-    return ret;
-
-  for (size_t i = 0; i < num_displays; ++i) {
-    hwc_display_contents_1_t *dc = sf_display_contents[i];
-    DrmHwcDisplayContents &display_contents = displays_contents[i];
-    if (!sf_display_contents[i] || i == HWC_DISPLAY_VIRTUAL)
-      continue;
-
-    layers_map.emplace_back();
-    DrmCompositionDisplayLayersMap &map = layers_map.back();
-    map.display = i;
-    map.geometry_changed =
-        (dc->flags & HWC_GEOMETRY_CHANGED) == HWC_GEOMETRY_CHANGED;
-    std::vector<size_t> &indices_to_composite = layers_indices[i];
-    for (size_t j : indices_to_composite) {
-      hwc_layer_1_t *sf_layer = &dc->hwLayers[j];
-
-      DrmHwcLayer &layer = display_contents.layers[j];
-
-      ret = layer.InitFromHwcLayer(sf_layer, ctx->importer.get(), ctx->gralloc);
-      if (ret) {
-        ALOGE("Failed to init composition from layer %d", ret);
-        return ret;
-      }
-      map.layers.emplace_back(std::move(layer));
-    }
-  }
-
-  std::unique_ptr<DrmComposition> composition(
-      ctx->drm.compositor()->CreateComposition(ctx->importer.get()));
-  if (!composition) {
-    ALOGE("Drm composition init failed");
-    return -EINVAL;
-  }
-
-  ret = composition->SetLayers(layers_map.size(), layers_map.data());
-  if (ret) {
-    return -EINVAL;
-  }
-
-  ret = ctx->drm.compositor()->QueueComposition(std::move(composition));
-  if (ret) {
-    return -EINVAL;
-  }
-
-  for (size_t i = 0; i < num_displays; ++i) {
-    hwc_display_contents_1_t *dc = sf_display_contents[i];
-    if (!dc)
-      continue;
-
-    size_t num_dc_layers = dc->numHwLayers;
-    for (size_t j = 0; j < num_dc_layers; ++j) {
-      hwc_layer_1_t *layer = &dc->hwLayers[j];
-      if (layer->flags & HWC_SKIP_LAYER)
-        continue;
-      hwc_add_layer_to_retire_fence(layer, dc);
-    }
-  }
-
-  composition.reset(NULL);
-
-  return ret;
-}
-
-static int hwc_event_control(struct hwc_composer_device_1 *dev, int display,
-                             int event, int enabled) {
-  if (event != HWC_EVENT_VSYNC || (enabled != 0 && enabled != 1))
-    return -EINVAL;
-
-  struct hwc_context_t *ctx = (struct hwc_context_t *)&dev->common;
-  hwc_drm_display_t *hd = &ctx->displays[display];
-  return hd->vsync_worker.VSyncControl(enabled);
-}
-
-static int hwc_set_power_mode(struct hwc_composer_device_1 *dev, int display,
-                              int mode) {
-  struct hwc_context_t *ctx = (struct hwc_context_t *)&dev->common;
-
-  uint64_t dpmsValue = 0;
-  switch (mode) {
-    case HWC_POWER_MODE_OFF:
-      dpmsValue = DRM_MODE_DPMS_OFF;
-      break;
-
-    /* We can't support dozing right now, so go full on */
-    case HWC_POWER_MODE_DOZE:
-    case HWC_POWER_MODE_DOZE_SUSPEND:
-    case HWC_POWER_MODE_NORMAL:
-      dpmsValue = DRM_MODE_DPMS_ON;
-      break;
-  };
-  return ctx->drm.SetDpmsMode(display, dpmsValue);
-}
-
-static int hwc_query(struct hwc_composer_device_1 * /* dev */, int what,
-                     int *value) {
-  switch (what) {
-    case HWC_BACKGROUND_LAYER_SUPPORTED:
-      *value = 0; /* TODO: We should do this */
-      break;
-    case HWC_VSYNC_PERIOD:
-      ALOGW("Query for deprecated vsync value, returning 60Hz");
-      *value = 1000 * 1000 * 1000 / 60;
-      break;
-    case HWC_DISPLAY_TYPES_SUPPORTED:
-      *value = HWC_DISPLAY_PRIMARY_BIT | HWC_DISPLAY_EXTERNAL_BIT |
-               HWC_DISPLAY_VIRTUAL_BIT;
-      break;
-  }
-  return 0;
-}
-
-static void hwc_register_procs(struct hwc_composer_device_1 *dev,
-                               hwc_procs_t const *procs) {
-  struct hwc_context_t *ctx = (struct hwc_context_t *)&dev->common;
-
-  ctx->procs = procs;
-
-  for (std::pair<const int, hwc_drm_display> &display_entry : ctx->displays) {
-    auto callback = std::make_shared<DrmVsyncCallback>(procs);
-    display_entry.second.vsync_worker.RegisterCallback(std::move(callback));
-  }
-
-  ctx->hotplug_handler.Init(&ctx->drm, procs);
-  ctx->drm.event_listener()->RegisterHotplugHandler(&ctx->hotplug_handler);
-}
-
-static int hwc_get_display_configs(struct hwc_composer_device_1 *dev,
-                                   int display, uint32_t *configs,
-                                   size_t *num_configs) {
-  if (!*num_configs)
-    return 0;
-
-  struct hwc_context_t *ctx = (struct hwc_context_t *)&dev->common;
-  hwc_drm_display_t *hd = &ctx->displays[display];
-  hd->config_ids.clear();
-
-  DrmConnector *connector = ctx->drm.GetConnectorForDisplay(display);
-  if (!connector) {
-    ALOGE("Failed to get connector for display %d", display);
-    return -ENODEV;
-  }
-
-  int ret = connector->UpdateModes();
-  if (ret) {
-    ALOGE("Failed to update display modes %d", ret);
-    return ret;
-  }
-
-  for (const DrmMode &mode : connector->modes()) {
-    size_t idx = hd->config_ids.size();
-    if (idx == *num_configs)
-      break;
-    hd->config_ids.push_back(mode.id());
-    configs[idx] = mode.id();
-  }
-  *num_configs = hd->config_ids.size();
-  return *num_configs == 0 ? -1 : 0;
-}
-
-static int hwc_get_display_attributes(struct hwc_composer_device_1 *dev,
-                                      int display, uint32_t config,
-                                      const uint32_t *attributes,
-                                      int32_t *values) {
-  struct hwc_context_t *ctx = (struct hwc_context_t *)&dev->common;
-  DrmConnector *c = ctx->drm.GetConnectorForDisplay(display);
-  if (!c) {
-    ALOGE("Failed to get DrmConnector for display %d", display);
-    return -ENODEV;
-  }
-  DrmMode mode;
-  for (const DrmMode &conn_mode : c->modes()) {
-    if (conn_mode.id() == config) {
-      mode = conn_mode;
-      break;
-    }
-  }
-  if (mode.id() == 0) {
-    ALOGE("Failed to find active mode for display %d", display);
-    return -ENOENT;
-  }
-
-  uint32_t mm_width = c->mm_width();
-  uint32_t mm_height = c->mm_height();
-  for (int i = 0; attributes[i] != HWC_DISPLAY_NO_ATTRIBUTE; ++i) {
-    switch (attributes[i]) {
-      case HWC_DISPLAY_VSYNC_PERIOD:
-        values[i] = 1000 * 1000 * 1000 / mode.v_refresh();
-        break;
-      case HWC_DISPLAY_WIDTH:
-        values[i] = mode.h_display();
-        break;
-      case HWC_DISPLAY_HEIGHT:
-        values[i] = mode.v_display();
-        break;
-      case HWC_DISPLAY_DPI_X:
-        /* Dots per 1000 inches */
-        values[i] = mm_width ? (mode.h_display() * UM_PER_INCH) / mm_width : 0;
-        break;
-      case HWC_DISPLAY_DPI_Y:
-        /* Dots per 1000 inches */
-        values[i] =
-            mm_height ? (mode.v_display() * UM_PER_INCH) / mm_height : 0;
-        break;
-    }
-  }
-  return 0;
-}
-
-static int hwc_get_active_config(struct hwc_composer_device_1 *dev,
-                                 int display) {
-  struct hwc_context_t *ctx = (struct hwc_context_t *)&dev->common;
-  DrmConnector *c = ctx->drm.GetConnectorForDisplay(display);
-  if (!c) {
-    ALOGE("Failed to get DrmConnector for display %d", display);
-    return -ENODEV;
-  }
-
-  DrmMode mode = c->active_mode();
-  hwc_drm_display_t *hd = &ctx->displays[display];
-  for (size_t i = 0; i < hd->config_ids.size(); ++i) {
-    if (hd->config_ids[i] == mode.id())
-      return i;
-  }
-  return -1;
-}
-
-static int hwc_set_active_config(struct hwc_composer_device_1 *dev, int display,
-                                 int index) {
-  struct hwc_context_t *ctx = (struct hwc_context_t *)&dev->common;
-  hwc_drm_display_t *hd = &ctx->displays[display];
-  if (index >= (int)hd->config_ids.size()) {
-    ALOGE("Invalid config index %d passed in", index);
-    return -EINVAL;
-  }
-
-  DrmConnector *c = ctx->drm.GetConnectorForDisplay(display);
-  if (!c) {
-    ALOGE("Failed to get connector for display %d", display);
-    return -ENODEV;
-  }
-
-  if (c->state() != DRM_MODE_CONNECTED)
-    return -ENODEV;
-
-  DrmMode mode;
-  for (const DrmMode &conn_mode : c->modes()) {
-    if (conn_mode.id() == hd->config_ids[index]) {
-      mode = conn_mode;
-      break;
-    }
-  }
-  if (mode.id() != hd->config_ids[index]) {
-    ALOGE("Could not find active mode for %d/%d", index, hd->config_ids[index]);
-    return -ENOENT;
-  }
-  int ret = ctx->drm.SetDisplayActiveMode(display, mode);
-  if (ret) {
-    ALOGE("Failed to set active config %d", ret);
-    return ret;
-  }
-  ret = ctx->drm.SetDpmsMode(display, DRM_MODE_DPMS_ON);
-  if (ret) {
-    ALOGE("Failed to set dpms mode on %d", ret);
-    return ret;
-  }
-  return ret;
-}
-
-static int hwc_device_close(struct hw_device_t *dev) {
-  struct hwc_context_t *ctx = (struct hwc_context_t *)dev;
-  delete ctx;
-  return 0;
-}
-
-/*
- * TODO: This function sets the active config to the first one in the list. This
- * should be fixed such that it selects the preferred mode for the display, or
- * some other, saner, method of choosing the config.
- */
-static int hwc_set_initial_config(hwc_drm_display_t *hd) {
-  uint32_t config;
-  size_t num_configs = 1;
-  int ret = hwc_get_display_configs(&hd->ctx->device, hd->display, &config,
-                                    &num_configs);
-  if (ret || !num_configs)
-    return 0;
-
-  ret = hwc_set_active_config(&hd->ctx->device, hd->display, 0);
-  if (ret) {
-    ALOGE("Failed to set active config d=%d ret=%d", hd->display, ret);
-    return ret;
-  }
-
-  return ret;
-}
-
-static int hwc_initialize_display(struct hwc_context_t *ctx, int display) {
-  hwc_drm_display_t *hd = &ctx->displays[display];
-  hd->ctx = ctx;
-  hd->display = display;
-
-  int ret = hwc_set_initial_config(hd);
-  if (ret) {
-    ALOGE("Failed to set initial config for d=%d ret=%d", display, ret);
-    return ret;
-  }
-
-  ret = hd->vsync_worker.Init(&ctx->drm, display);
-  if (ret) {
-    ALOGE("Failed to create event worker for display %d %d\n", display, ret);
-    return ret;
-  }
-
-  return 0;
-}
-
-static int hwc_enumerate_displays(struct hwc_context_t *ctx) {
-  int ret;
-  for (auto &conn : ctx->drm.connectors()) {
-    ret = hwc_initialize_display(ctx, conn->display());
-    if (ret) {
-      ALOGE("Failed to initialize display %d", conn->display());
-      return ret;
-    }
-  }
-
-  ret = ctx->virtual_compositor_worker.Init();
-  if (ret) {
-    ALOGE("Failed to initialize virtual compositor worker");
-    return ret;
-  }
-  return 0;
-}
-
-static int hwc_device_open(const struct hw_module_t *module, const char *name,
-                           struct hw_device_t **dev) {
-  if (strcmp(name, HWC_HARDWARE_COMPOSER)) {
-    ALOGE("Invalid module name- %s", name);
-    return -EINVAL;
-  }
-
-  std::unique_ptr<hwc_context_t> ctx(new hwc_context_t());
-  if (!ctx) {
-    ALOGE("Failed to allocate hwc context");
-    return -ENOMEM;
-  }
-
-  int ret = ctx->drm.Init();
-  if (ret) {
-    ALOGE("Can't initialize Drm object %d", ret);
-    return ret;
-  }
-
-  ret = hw_get_module(GRALLOC_HARDWARE_MODULE_ID,
-                      (const hw_module_t **)&ctx->gralloc);
-  if (ret) {
-    ALOGE("Failed to open gralloc module %d", ret);
-    return ret;
-  }
-
-  ret = ctx->dummy_timeline.Init();
-  if (ret) {
-    ALOGE("Failed to create dummy sw sync timeline %d", ret);
-    return ret;
-  }
-
-  ctx->importer.reset(Importer::CreateInstance(&ctx->drm));
-  if (!ctx->importer) {
-    ALOGE("Failed to create importer instance");
-    return ret;
-  }
-
-  ret = hwc_enumerate_displays(ctx.get());
-  if (ret) {
-    ALOGE("Failed to enumerate displays: %s", strerror(ret));
-    return ret;
-  }
-
-  ctx->device.common.tag = HARDWARE_DEVICE_TAG;
-  ctx->device.common.version = HWC_DEVICE_API_VERSION_1_4;
-  ctx->device.common.module = const_cast<hw_module_t *>(module);
-  ctx->device.common.close = hwc_device_close;
-
-  ctx->device.dump = hwc_dump;
-  ctx->device.prepare = hwc_prepare;
-  ctx->device.set = hwc_set;
-  ctx->device.eventControl = hwc_event_control;
-  ctx->device.setPowerMode = hwc_set_power_mode;
-  ctx->device.query = hwc_query;
-  ctx->device.registerProcs = hwc_register_procs;
-  ctx->device.getDisplayConfigs = hwc_get_display_configs;
-  ctx->device.getDisplayAttributes = hwc_get_display_attributes;
-  ctx->device.getActiveConfig = hwc_get_active_config;
-  ctx->device.setActiveConfig = hwc_set_active_config;
-  ctx->device.setCursorPositionAsync = NULL; /* TODO: Add cursor */
-
-  *dev = &ctx->device.common;
-  ctx.release();
-
-  return 0;
-}
-}
-
-static struct hw_module_methods_t hwc_module_methods = {
-  .open = android::hwc_device_open
-};
-
-hwc_module_t HAL_MODULE_INFO_SYM = {
-  .common = {
-    .tag = HARDWARE_MODULE_TAG,
-    .version_major = 1,
-    .version_minor = 0,
-    .id = HWC_HARDWARE_MODULE_ID,
-    .name = "DRM hwcomposer module",
-    .author = "The Android Open Source Project",
-    .methods = &hwc_module_methods,
-    .dso = NULL,
-    .reserved = {0},
-  }
-};