drm_hwcomposer: Dynamic DrmDisplayPipeline to HwcDisplay bindings

The following use scenarios are now possible:

1. When no display connected, primary HwcDisplay is created in headless
   mode.

2. When user connects first display, it binds to primary slot, replacing
   headless HwcDisplay.

3. When user connects another display it binds to the new HwcDisplay
   slot, creating new display for the framework.

4. When user disconnects first (Primary) display, drm_hwc detaches
   second display and attaches it to the Primary slot. In this case
   framework is notified as Primary display resolution updated
   (Plugged->Plugged transition). And second display is disconnected
   (Plugged->Unplugged transition).

DrmDisplayPipeline is now created on demand (after hotplug event).

HwcDisplay class is now destructed on connector unplug, which will give
us ability to destroy any resource caches (will be required for FB
caching logic).

Signed-off-by: Roman Stratiienko <roman.o.stratiienko@globallogic.com>

4 files changed, 132 insertions, 103 deletions

diff --git a/drm/DrmDevice.cpp b/drm/DrmDevice.cpp
index d1ae7c9..e5f41e8 100644
--- a/drm/DrmDevice.cpp
+++ b/drm/DrmDevice.cpp
@@ -22,12 +22,8 @@
 #include <xf86drm.h>
 #include <xf86drmMode.h>
 
-#include <algorithm>
-#include <array>
-#include <cerrno>
 #include <cinttypes>
 #include <cstdint>
-#include <sstream>
 #include <string>
 
 #include "compositor/DrmDisplayCompositor.h"
@@ -41,26 +37,25 @@ DrmDevice::DrmDevice() {
   drm_fb_importer_ = std::make_unique<DrmFbImporter>(*this);
 }
 
-// NOLINTNEXTLINE (readability-function-cognitive-complexity): Fixme
-std::tuple<int, int> DrmDevice::Init(const char *path, int num_displays) {
+auto DrmDevice::Init(const char *path) -> int {
   /* TODO: Use drmOpenControl here instead */
   fd_ = UniqueFd(open(path, O_RDWR | O_CLOEXEC));
   if (!fd_) {
     // NOLINTNEXTLINE(concurrency-mt-unsafe): Fixme
     ALOGE("Failed to open dri %s: %s", path, strerror(errno));
-    return std::make_tuple(-ENODEV, 0);
+    return -ENODEV;
   }
 
   int ret = drmSetClientCap(GetFd(), DRM_CLIENT_CAP_UNIVERSAL_PLANES, 1);
   if (ret != 0) {
     ALOGE("Failed to set universal plane cap %d", ret);
-    return std::make_tuple(ret, 0);
+    return ret;
   }
 
   ret = drmSetClientCap(GetFd(), DRM_CLIENT_CAP_ATOMIC, 1);
   if (ret != 0) {
     ALOGE("Failed to set atomic cap %d", ret);
-    return std::make_tuple(ret, 0);
+    return ret;
   }
 
 #ifdef DRM_CLIENT_CAP_WRITEBACK_CONNECTORS
@@ -80,13 +75,13 @@ std::tuple<int, int> DrmDevice::Init(const char *path, int num_displays) {
   drmSetMaster(GetFd());
   if (drmIsMaster(GetFd()) == 0) {
     ALOGE("DRM/KMS master access required");
-    return std::make_tuple(-EACCES, 0);
+    return -EACCES;
   }
 
   auto res = MakeDrmModeResUnique(GetFd());
   if (!res) {
     ALOGE("Failed to get DrmDevice resources");
-    return std::make_tuple(-ENODEV, 0);
+    return -ENODEV;
   }
 
   min_resolution_ = std::pair<uint32_t, uint32_t>(res->min_width,
@@ -128,7 +123,7 @@ std::tuple<int, int> DrmDevice::Init(const char *path, int num_displays) {
   auto plane_res = MakeDrmModePlaneResUnique(GetFd());
   if (!plane_res) {
     ALOGE("Failed to get plane resources");
-    return std::make_tuple(-ENOENT, 0);
+    return -ENOENT;
   }
 
   for (uint32_t i = 0; i < plane_res->count_planes; ++i) {
@@ -140,42 +135,7 @@ std::tuple<int, int> DrmDevice::Init(const char *path, int num_displays) {
     }
   }
 
-  auto add_displays = [this, &num_displays](bool internal, bool connected) {
-    for (auto &conn : connectors_) {
-      bool is_connected = conn->IsConnected();
-      if ((internal ? conn->IsInternal() : conn->IsExternal()) &&
-          (connected ? is_connected : !is_connected)) {
-        auto pipe = DrmDisplayPipeline::CreatePipeline(*conn);
-        if (pipe) {
-          pipelines_[num_displays] = std::move(pipe);
-          ++num_displays;
-        }
-      }
-    }
-  };
-
-  /* Put internal first to ensure Primary display will be internal
-   * in case at least 1 internal is available
-   */
-  add_displays(/*internal = */ true, /*connected = */ true);
-  add_displays(/*internal = */ false, /*connected = */ true);
-  add_displays(/*internal = */ true, /*connected = */ false);
-  add_displays(/*internal = */ false, /*connected = */ false);
-
-  return std::make_tuple(0, pipelines_.size());
-}
-
-bool DrmDevice::HandlesDisplay(int display) const {
-  return pipelines_.count(display) != 0;
-}
-
-auto DrmDevice::GetDisplayId(DrmConnector *conn) -> int {
-  for (auto &dpipe : pipelines_) {
-    if (dpipe.second->connector->Get() == conn) {
-      return dpipe.first;
-    }
-  }
-  return -1;
+  return 0;
 }
 
 auto DrmDevice::RegisterUserPropertyBlob(void *data, size_t length) const
diff --git a/drm/DrmDevice.h b/drm/DrmDevice.h
index 5220760..f2530ee 100644
--- a/drm/DrmDevice.h
+++ b/drm/DrmDevice.h
@@ -37,7 +37,7 @@ class DrmDevice {
   DrmDevice();
   ~DrmDevice() = default;
 
-  std::tuple<int, int> Init(const char *path, int num_displays);
+  auto Init(const char *path) -> int;
 
   auto GetFd() const {
     return fd_.Get();
@@ -56,19 +56,12 @@ class DrmDevice {
     return max_resolution_;
   }
 
-  auto *GetPipelineForDisplay(int display) {
-    return pipelines_.count(display) != 0 ? pipelines_.at(display).get()
-                                          : nullptr;
-  }
-
   std::string GetName() const;
 
   auto RegisterUserPropertyBlob(void *data, size_t length) const
       -> DrmModeUserPropertyBlobUnique;
 
-  bool HandlesDisplay(int display) const;
-
-  bool HasAddFb2ModifiersSupport() const {
+  auto HasAddFb2ModifiersSupport() const {
     return HasAddFb2ModifiersSupport_;
   }
 
@@ -98,8 +91,6 @@ class DrmDevice {
     return nullptr;
   }
 
-  auto GetDisplayId(DrmConnector *conn) -> int;
-
   int GetProperty(uint32_t obj_id, uint32_t obj_type, const char *prop_name,
                   DrmProperty *property) const;
 
@@ -115,8 +106,6 @@ class DrmDevice {
   std::pair<uint32_t, uint32_t> min_resolution_;
   std::pair<uint32_t, uint32_t> max_resolution_;
 
-  std::map<int /*display*/, std::unique_ptr<DrmDisplayPipeline>> pipelines_;
-
   bool HasAddFb2ModifiersSupport_{};
 
   std::unique_ptr<DrmFbImporter> drm_fb_importer_;
diff --git a/drm/ResourceManager.cpp b/drm/ResourceManager.cpp
index a7d99ee..789eca3 100644
--- a/drm/ResourceManager.cpp
+++ b/drm/ResourceManager.cpp
@@ -33,25 +33,34 @@
 
 namespace android {
 
-ResourceManager::ResourceManager() : num_displays_(0) {
+ResourceManager::ResourceManager(
+    PipelineToFrontendBindingInterface *p2f_bind_interface)
+    : frontend_interface_(p2f_bind_interface) {
+  if (uevent_listener_.Init() != 0) {
+    ALOGE("Can't initialize event listener");
+  }
 }
 
 ResourceManager::~ResourceManager() {
   uevent_listener_.Exit();
 }
 
-int ResourceManager::Init() {
+void ResourceManager::Init() {
+  if (initialized_) {
+    ALOGE("Already initialized");
+    return;
+  }
+
   char path_pattern[PROPERTY_VALUE_MAX];
   // Could be a valid path or it can have at the end of it the wildcard %
   // which means that it will try open all devices until an error is met.
   int path_len = property_get("vendor.hwc.drm.device", path_pattern,
                               "/dev/dri/card%");
-  int ret = 0;
   if (path_pattern[path_len - 1] != '%') {
-    ret = AddDrmDevice(std::string(path_pattern));
+    AddDrmDevice(std::string(path_pattern));
   } else {
     path_pattern[path_len - 1] = '\0';
-    for (int idx = 0; ret == 0; ++idx) {
+    for (int idx = 0;; ++idx) {
       std::ostringstream path;
       path << path_pattern << idx;
 
@@ -59,51 +68,109 @@ int ResourceManager::Init() {
       if (stat(path.str().c_str(), &buf) != 0)
         break;
 
-      if (DrmDevice::IsKMSDev(path.str().c_str()))
-        ret = AddDrmDevice(path.str());
+      if (DrmDevice::IsKMSDev(path.str().c_str())) {
+        AddDrmDevice(path.str());
+      }
     }
   }
 
-  if (num_displays_ == 0) {
-    ALOGE("Failed to initialize any displays");
-    return ret != 0 ? -EINVAL : ret;
-  }
-
   char scale_with_gpu[PROPERTY_VALUE_MAX];
   property_get("vendor.hwc.drm.scale_with_gpu", scale_with_gpu, "0");
   scale_with_gpu_ = bool(strncmp(scale_with_gpu, "0", 1));
 
   if (BufferInfoGetter::GetInstance() == nullptr) {
     ALOGE("Failed to initialize BufferInfoGetter");
-    return -EINVAL;
+    return;
   }
 
-  ret = uevent_listener_.Init();
-  if (ret != 0) {
-    ALOGE("Can't initialize event listener %d", ret);
-    return ret;
+  uevent_listener_.RegisterHotplugHandler([this] {
+    const std::lock_guard<std::mutex> lock(GetMainLock());
+    UpdateFrontendDisplays();
+  });
+
+  UpdateFrontendDisplays();
+
+  initialized_ = true;
+}
+
+void ResourceManager::DeInit() {
+  if (!initialized_) {
+    ALOGE("Not initialized");
+    return;
   }
 
-  return 0;
+  uevent_listener_.RegisterHotplugHandler([] {});
+
+  DetachAllFrontendDisplays();
+  drms_.clear();
+
+  initialized_ = false;
 }
 
 int ResourceManager::AddDrmDevice(const std::string &path) {
   auto drm = std::make_unique<DrmDevice>();
-  int displays_added = 0;
-  int ret = 0;
-  std::tie(ret, displays_added) = drm->Init(path.c_str(), num_displays_);
+  int ret = drm->Init(path.c_str());
   drms_.push_back(std::move(drm));
-  num_displays_ += displays_added;
   return ret;
 }
 
-DrmDisplayPipeline *ResourceManager::GetPipeline(int display) {
+void ResourceManager::UpdateFrontendDisplays() {
+  auto ordered_connectors = GetOrderedConnectors();
+
+  for (auto *conn : ordered_connectors) {
+    conn->UpdateModes();
+    bool connected = conn->IsConnected();
+    bool attached = attached_pipelines_.count(conn) != 0;
+
+    if (connected != attached) {
+      ALOGI("%s connector %s", connected ? "Attaching" : "Detaching",
+            conn->GetName().c_str());
+
+      if (connected) {
+        auto pipeline = DrmDisplayPipeline::CreatePipeline(*conn);
+        frontend_interface_->BindDisplay(pipeline.get());
+        attached_pipelines_[conn] = std::move(pipeline);
+      } else {
+        auto &pipeline = attached_pipelines_[conn];
+        frontend_interface_->UnbindDisplay(pipeline.get());
+        attached_pipelines_.erase(conn);
+      }
+    }
+  }
+  frontend_interface_->FinalizeDisplayBinding();
+}
+
+void ResourceManager::DetachAllFrontendDisplays() {
+  for (auto &p : attached_pipelines_) {
+    frontend_interface_->UnbindDisplay(p.second.get());
+  }
+  attached_pipelines_.clear();
+  frontend_interface_->FinalizeDisplayBinding();
+}
+
+auto ResourceManager::GetOrderedConnectors() -> std::vector<DrmConnector *> {
+  /* Put internal displays first then external to
+   * ensure Internal will take Primary slot
+   */
+
+  std::vector<DrmConnector *> ordered_connectors;
+
+  for (auto &drm : drms_) {
+    for (const auto &conn : drm->GetConnectors()) {
+      if (conn->IsInternal()) {
+        ordered_connectors.emplace_back(conn.get());
+      }
+    }
+  }
+
   for (auto &drm : drms_) {
-    auto *pipe = drm->GetPipelineForDisplay(display);
-    if (pipe != nullptr) {
-      return pipe;
+    for (const auto &conn : drm->GetConnectors()) {
+      if (conn->IsExternal()) {
+        ordered_connectors.emplace_back(conn.get());
+      }
     }
   }
-  return nullptr;
+
+  return ordered_connectors;
 }
 }  // namespace android
diff --git a/drm/ResourceManager.h b/drm/ResourceManager.h
index caeb098..c4c3edd 100644
--- a/drm/ResourceManager.h
+++ b/drm/ResourceManager.h
@@ -20,42 +20,48 @@
 #include <cstring>
 
 #include "DrmDevice.h"
+#include "DrmDisplayPipeline.h"
 #include "DrmFbImporter.h"
 #include "UEventListener.h"
 
 namespace android {
 
+class PipelineToFrontendBindingInterface {
+ public:
+  virtual ~PipelineToFrontendBindingInterface() = default;
+  virtual bool BindDisplay(DrmDisplayPipeline *);
+  virtual bool UnbindDisplay(DrmDisplayPipeline *);
+  virtual void FinalizeDisplayBinding();
+};
+
 class ResourceManager {
  public:
-  ResourceManager();
+  explicit ResourceManager(
+      PipelineToFrontendBindingInterface *p2f_bind_interface);
   ResourceManager(const ResourceManager &) = delete;
   ResourceManager &operator=(const ResourceManager &) = delete;
+  ResourceManager(const ResourceManager &&) = delete;
+  ResourceManager &&operator=(const ResourceManager &&) = delete;
   ~ResourceManager();
 
-  int Init();
-  auto GetPipeline(int display) -> DrmDisplayPipeline *;
-  auto &GetDrmDevices() const {
-    return drms_;
-  }
-  int GetDisplayCount() const {
-    return num_displays_;
-  }
+  void Init();
+
+  void DeInit();
+
   bool ForcedScalingWithGpu() const {
     return scale_with_gpu_;
   }
 
-  UEventListener *GetUEventListener() {
-    return &uevent_listener_;
-  }
-
   auto &GetMainLock() {
     return main_lock_;
   }
 
  private:
-  int AddDrmDevice(std::string const &path);
+  auto AddDrmDevice(std::string const &path) -> int;
+  auto GetOrderedConnectors() -> std::vector<DrmConnector *>;
+  void UpdateFrontendDisplays();
+  void DetachAllFrontendDisplays();
 
-  int num_displays_;
   std::vector<std::unique_ptr<DrmDevice>> drms_;
 
   bool scale_with_gpu_{};
@@ -63,6 +69,13 @@ class ResourceManager {
   UEventListener uevent_listener_;
 
   std::mutex main_lock_;
+
+  std::map<DrmConnector *, std::unique_ptr<DrmDisplayPipeline>>
+      attached_pipelines_;
+
+  PipelineToFrontendBindingInterface *const frontend_interface_;
+
+  bool initialized_{};
 };
 }  // namespace android