diff --git a/compositor/DrmDisplayComposition.cpp b/compositor/DrmDisplayComposition.cpp
index 4d2e19a..1e9e127 100644
--- a/compositor/DrmDisplayComposition.cpp
+++ b/compositor/DrmDisplayComposition.cpp
@@ -19,11 +19,11 @@
 #include "DrmDisplayComposition.h"
 
 #include <log/log.h>
-#include <stdlib.h>
 #include <sync/sync.h>
 #include <xf86drmMode.h>
 
 #include <algorithm>
+#include <cstdlib>
 #include <unordered_set>
 
 #include "DrmDisplayCompositor.h"
@@ -32,9 +32,6 @@
 
 namespace android {
 
-DrmDisplayComposition::~DrmDisplayComposition() {
-}
-
 int DrmDisplayComposition::Init(DrmDevice *drm, DrmCrtc *crtc,
                                 Importer *importer, Planner *planner,
                                 uint64_t frame_no) {
@@ -211,7 +208,7 @@
     separator = true;
   }
 
-  uint32_t valid_bits = DrmHwcTransform::kFlipH | DrmHwcTransform::kFlipH |
+  uint32_t valid_bits = DrmHwcTransform::kFlipH | DrmHwcTransform::kFlipV |
                         DrmHwcTransform::kRotate90 |
                         DrmHwcTransform::kRotate180 |
                         DrmHwcTransform::kRotate270;
diff --git a/compositor/DrmDisplayComposition.h b/compositor/DrmDisplayComposition.h
index 73a9024..5d99d23 100644
--- a/compositor/DrmDisplayComposition.h
+++ b/compositor/DrmDisplayComposition.h
@@ -109,7 +109,7 @@
  public:
   DrmDisplayComposition() = default;
   DrmDisplayComposition(const DrmDisplayComposition &) = delete;
-  ~DrmDisplayComposition();
+  ~DrmDisplayComposition() = default;
 
   int Init(DrmDevice *drm, DrmCrtc *crtc, Importer *importer, Planner *planner,
            uint64_t frame_no);
diff --git a/compositor/DrmDisplayCompositor.cpp b/compositor/DrmDisplayCompositor.cpp
index 3ae42ef..b33c9c0 100644
--- a/compositor/DrmDisplayCompositor.cpp
+++ b/compositor/DrmDisplayCompositor.cpp
@@ -23,12 +23,12 @@
 #include <log/log.h>
 #include <pthread.h>
 #include <sched.h>
-#include <stdlib.h>
 #include <sync/sync.h>
-#include <time.h>
 #include <utils/Trace.h>
 
 #include <array>
+#include <cstdlib>
+#include <ctime>
 #include <sstream>
 #include <vector>
 
@@ -52,11 +52,11 @@
 
 class CompositorVsyncCallback : public VsyncCallback {
  public:
-  CompositorVsyncCallback(DrmDisplayCompositor *compositor)
+  explicit CompositorVsyncCallback(DrmDisplayCompositor *compositor)
       : compositor_(compositor) {
   }
 
-  void Callback(int display, int64_t timestamp) {
+  void Callback(int display, int64_t timestamp) override {
     compositor_->Vsync(display, timestamp);
   }
 
@@ -65,7 +65,7 @@
 };
 
 DrmDisplayCompositor::DrmDisplayCompositor()
-    : resource_manager_(NULL),
+    : resource_manager_(nullptr),
       display_(-1),
       initialized_(false),
       active_(false),
@@ -113,7 +113,7 @@
     ALOGE("Could not find drmdevice for display");
     return -EINVAL;
   }
-  int ret = pthread_mutex_init(&lock_, NULL);
+  int ret = pthread_mutex_init(&lock_, nullptr);
   if (ret) {
     ALOGE("Failed to initialize drm compositor lock %d\n", ret);
     return ret;
@@ -130,7 +130,7 @@
 
 std::unique_ptr<DrmDisplayComposition> DrmDisplayCompositor::CreateComposition()
     const {
-  return std::unique_ptr<DrmDisplayComposition>(new DrmDisplayComposition());
+  return std::make_unique<DrmDisplayComposition>();
 }
 
 std::unique_ptr<DrmDisplayComposition>
@@ -172,7 +172,7 @@
 DrmDisplayCompositor::GetActiveModeResolution() {
   DrmDevice *drm = resource_manager_->GetDrmDevice(display_);
   DrmConnector *connector = drm->GetConnectorForDisplay(display_);
-  if (connector == NULL) {
+  if (connector == nullptr) {
     ALOGE("Failed to determine display mode: no connector for display %d",
           display_);
     return std::make_tuple(0, 0, -ENODEV);
@@ -286,8 +286,8 @@
     return -ENOMEM;
   }
 
-  if (writeback_buffer != NULL) {
-    if (writeback_conn == NULL) {
+  if (writeback_buffer != nullptr) {
+    if (writeback_conn == nullptr) {
       ALOGE("Invalid arguments requested writeback without writeback conn");
       return -EINVAL;
     }
@@ -661,7 +661,7 @@
   if (DisablePlanes(active_composition_.get()))
     return;
 
-  active_composition_.reset(NULL);
+  active_composition_.reset(nullptr);
   vsync_worker_.VSyncControl(false);
 }
 
@@ -785,8 +785,8 @@
     ALOGE("Failed to find crtc for display %d", display_);
     return -EINVAL;
   }
-  // TODO what happens if planes could go to both CRTCs, I don't think it's
-  // handled anywhere
+  // TODO(nobody) what happens if planes could go to both CRTCs, I don't think
+  // it's handled anywhere
   std::vector<DrmPlane *> primary_planes;
   std::vector<DrmPlane *> overlay_planes;
   for (auto &plane : drm->planes()) {
@@ -896,10 +896,10 @@
     SetFlattening(FlatteningState::kClientRequested);
     refresh_callback_hook_(refresh_callback_data_, display_);
     return 0;
-  } else {
-    ALOGV("No writeback connector available");
-    return -EINVAL;
   }
+
+  ALOGV("No writeback connector available");
+  return -EINVAL;
 }
 
 // Flatten a scene by enabling the writeback connector attached
@@ -976,7 +976,7 @@
     return ret;
   }
 
-  DrmCompositionPlane squashed_comp(DrmCompositionPlane::Type::kLayer, NULL,
+  DrmCompositionPlane squashed_comp(DrmCompositionPlane::Type::kLayer, nullptr,
                                     crtc);
   for (auto &drmplane : drm->planes()) {
     if (!drmplane->GetCrtcSupported(*crtc))
@@ -1061,7 +1061,7 @@
     return ret;
   }
 
-  DrmCompositionPlane squashed_comp(DrmCompositionPlane::Type::kLayer, NULL,
+  DrmCompositionPlane squashed_comp(DrmCompositionPlane::Type::kLayer, nullptr,
                                     crtc);
   for (auto &drmplane : resource_manager_->GetDrmDevice(display_)->planes()) {
     if (!drmplane->GetCrtcSupported(*crtc))
@@ -1106,12 +1106,10 @@
   if (writeback_conn->display() != display_) {
     SetFlattening(FlatteningState::kConcurrent);
     return FlattenConcurrent(writeback_conn);
-  } else {
-    SetFlattening(FlatteningState::kSerial);
-    return FlattenSerial(writeback_conn);
   }
 
-  return 0;
+  SetFlattening(FlatteningState::kSerial);
+  return FlattenSerial(writeback_conn);
 }
 
 bool DrmDisplayCompositor::CountdownExpired() const {
@@ -1149,7 +1147,7 @@
 
   uint64_t cur_ts = ts.tv_sec * 1000 * 1000 * 1000 + ts.tv_nsec;
   uint64_t num_ms = (cur_ts - dump_last_timestamp_ns_) / (1000 * 1000);
-  float fps = num_ms ? (num_frames * 1000.0f) / (num_ms) : 0.0f;
+  float fps = num_ms ? (num_frames * 1000.0F) / (num_ms) : 0.0F;
 
   *out << "--DrmDisplayCompositor[" << display_
        << "]: num_frames=" << num_frames << " num_ms=" << num_ms
diff --git a/compositor/Planner.cpp b/compositor/Planner.cpp
index f4b5c51..fb6a8c3 100644
--- a/compositor/Planner.cpp
+++ b/compositor/Planner.cpp
@@ -24,7 +24,7 @@
 
 namespace android {
 
-std::unique_ptr<Planner> Planner::CreateInstance(DrmDevice *) {
+std::unique_ptr<Planner> Planner::CreateInstance(DrmDevice * /*device*/) {
   std::unique_ptr<Planner> planner(new Planner);
   planner->AddStage<PlanStageGreedy>();
   return planner;
@@ -123,7 +123,6 @@
     std::map<size_t, DrmHwcLayer *> &layers, DrmCrtc *crtc,
     std::vector<DrmPlane *> *planes) {
   int ret;
-  int protected_zorder = -1;
   for (auto i = layers.begin(); i != layers.end();) {
     if (!i->second->protected_usage()) {
       ++i;
@@ -137,7 +136,6 @@
       return ret;
     }
 
-    protected_zorder = i->first;
     i = layers.erase(i);
   }
 
@@ -155,7 +153,8 @@
     // We don't have any planes left
     if (ret == -ENOENT)
       break;
-    else if (ret) {
+
+    if (ret) {
       ALOGE("Failed to emplace layer %zu, dropping it", i->first);
       return ret;
     }