[Ozone-Dri] Gracefully handle DRM devices with no resources

DRM devices such as VGEM do not have resources, so we want to ignore
them rather than crash.

BUG=460982

Review URL: https://codereview.chromium.org/947293002

Cr-Commit-Position: refs/heads/master@{#317687}

ui/ozone/platform/dri/dri_wrapper.cc

@@ -88,6 +88,14 @@ void HandlePageFlipEventOnUI(int fd,
   payload->callback.Run(frame, seconds, useconds);
 }
 
+bool CanQueryForResources(int fd) {
+  drm_mode_card_res resources;
+  memset(&resources, 0, sizeof(resources));
+  // If there is no error getting DRM resources then assume this is a
+  // modesetting device.
+  return !drmIoctl(fd, DRM_IOCTL_MODE_GETRESOURCES, &resources);
+}
+
 }  // namespace
 
 class DriWrapper::IOWatcher
@@ -163,10 +171,23 @@ DriWrapper::~DriWrapper() {
     watcher_->Shutdown();
 }
 
-void DriWrapper::Initialize() {
+bool DriWrapper::Initialize() {
+  // Ignore devices that cannot perform modesetting.
+  if (!CanQueryForResources(file_.GetPlatformFile())) {
+    VLOG(2) << "Cannot query for resources for '" << device_path_.value()
+            << "'";
+    return false;
+  }
+
   plane_manager_.reset(new HardwareDisplayPlaneManagerLegacy());
-  if (!plane_manager_->Initialize(this))
-    LOG(ERROR) << "Failed to initialize the plane manager";
+  if (!plane_manager_->Initialize(this)) {
+    LOG(ERROR) << "Failed to initialize the plane manager for "
+               << device_path_.value();
+    plane_manager_.reset();
+    return false;
+  }
+
+  return true;
 }
 
 void DriWrapper::InitializeTaskRunner(

ui/ozone/platform/dri/dri_wrapper.h

@@ -48,7 +48,7 @@ class OZONE_EXPORT DriWrapper : public base::RefCountedThreadSafe<DriWrapper> {
   DriWrapper(const base::FilePath& device_path, base::File file);
 
   // Open device.
-  virtual void Initialize();
+  virtual bool Initialize();
 
   // |task_runner| will be used to asynchronously page flip.
   virtual void InitializeTaskRunner(

ui/ozone/platform/dri/drm_device_generator.cc

@@ -18,8 +18,10 @@ scoped_refptr<DriWrapper> DrmDeviceGenerator::CreateDevice(
     const base::FilePath& device_path,
     base::File file) {
   scoped_refptr<DriWrapper> drm = new DriWrapper(device_path, file.Pass());
-  drm->Initialize();
-  return drm;
+  if (drm->Initialize())
+    return drm;
+
+  return nullptr;
 }
 
 }  // namespace ui

ui/ozone/platform/dri/gbm_wrapper.cc

@@ -21,11 +21,17 @@ GbmWrapper::~GbmWrapper() {
     gbm_device_destroy(device_);
 }
 
-void GbmWrapper::Initialize() {
-  DriWrapper::Initialize();
+bool GbmWrapper::Initialize() {
+  if (!DriWrapper::Initialize())
+    return false;
+
   device_ = gbm_create_device(get_fd());
-  if (!device_)
-    LOG(FATAL) << "Unable to initialize GBM";
+  if (!device_) {
+    LOG(ERROR) << "Unable to initialize GBM";
+    return false;
+  }
+
+  return true;
 }
 
 }  // namespace ui

ui/ozone/platform/dri/gbm_wrapper.h

@@ -19,7 +19,7 @@ class GbmWrapper : public DriWrapper {
   gbm_device* device() const { return device_; }
 
   // DriWrapper implementation:
-  void Initialize() override;
+  bool Initialize() override;
 
  private:
   ~GbmWrapper() override;

ui/ozone/platform/dri/hardware_display_plane_manager.cc

@@ -69,7 +69,7 @@ bool HardwareDisplayPlaneManager::Initialize(DriWrapper* drm) {
   drm_ = drm;
   ScopedDrmResourcesPtr resources(drmModeGetResources(drm->get_fd()));
   if (!resources) {
-    LOG(ERROR) << "Failed to get resources.";
+    PLOG(ERROR) << "Failed to get resources";
     return false;
   }
 

ui/ozone/platform/dri/native_display_delegate_dri.cc

@@ -219,13 +219,17 @@ void NativeDisplayDelegateDri::AddGraphicsDevice(
   auto it =
       std::find_if(devices_.begin(), devices_.end(), FindByDevicePath(path));
   if (it != devices_.end()) {
-    LOG(WARNING) << "Got request to add existing device '" << path.value()
-                 << "'";
+    VLOG(2) << "Got request to add existing device '" << path.value() << "'";
     return;
   }
 
   scoped_refptr<DriWrapper> device =
       drm_device_generator_->CreateDevice(path, file.Pass());
+  if (!device) {
+    VLOG(2) << "Could not initialize DRM device for '" << path.value() << "'";
+    return;
+  }
+
   devices_.push_back(device);
   if (io_task_runner_)
     device->InitializeTaskRunner(io_task_runner_);
@@ -236,8 +240,8 @@ void NativeDisplayDelegateDri::RemoveGraphicsDevice(
   auto it =
       std::find_if(devices_.begin(), devices_.end(), FindByDevicePath(path));
   if (it == devices_.end()) {
-    LOG(ERROR) << "Got request to remove non-existent device '" << path.value()
-               << "'";
+    VLOG(2) << "Got request to remove non-existent device '" << path.value()
+            << "'";
     return;
   }
 

ui/ozone/platform/dri/ozone_platform_dri.cc

@@ -91,7 +91,9 @@ class OzonePlatformDri : public OzonePlatform {
         display_manager_.get()));
   }
   void InitializeUI() override {
-    dri_->Initialize();
+    if (!dri_->Initialize())
+      LOG(FATAL) << "Failed to initialize primary DRM device";
+
     // This makes sure that simple targets that do not handle display
     // configuration can still use the primary display.
     ForceInitializationOfPrimaryDisplay(dri_, screen_manager_.get());

ui/ozone/platform/dri/ozone_platform_gbm.cc

@@ -96,8 +96,10 @@ class GbmDeviceGenerator : public DrmDeviceGenerator {
   scoped_refptr<DriWrapper> CreateDevice(const base::FilePath& path,
                                          base::File file) override {
     scoped_refptr<DriWrapper> drm = new GbmWrapper(path, file.Pass());
-    drm->Initialize();
-    return drm;
+    if (drm->Initialize())
+      return drm;
+
+    return nullptr;
   }
 
  private:
@@ -173,7 +175,9 @@ class OzonePlatformGbm : public OzonePlatform {
     gl_api_loader_.reset(new GlApiLoader());
     // Async page flips are supported only on surfaceless mode.
     gbm_ = new GbmWrapper(GetFirstDisplayCardPath());
-    gbm_->Initialize();
+    if (!gbm_->Initialize())
+      LOG(FATAL) << "Failed to initialize primary DRM device";
+
     drm_device_manager_.reset(new DrmDeviceManager(gbm_));
     buffer_generator_.reset(new GbmBufferGenerator());
     screen_manager_.reset(new ScreenManager(buffer_generator_.get()));