[2/4]Allow hotplugging of primary DRM device

ui/ozone/platform/drm/host/drm_native_display_delegate.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ui/ozone/platform/drm/host/drm_native_display_delegate.h"
 
 #include <stdio.h>
+#include <xf86drm.h>
 
 #include "base/logging.h"
 #include "base/thread_task_runner_handle.h"
 #include "base/threading/sequenced_worker_pool.h"
 #include "base/threading/thread_restrictions.h"
 #include "ui/display/types/display_snapshot.h"
 #include "ui/display/types/native_display_observer.h"
 #include "ui/events/ozone/device/device_event.h"
 #include "ui/events/ozone/device/device_manager.h"
 #include "ui/ozone/common/display_snapshot_proxy.h"
 #include "ui/ozone/common/display_util.h"
 #include "ui/ozone/common/gpu/ozone_gpu_messages.h"
 #include "ui/ozone/platform/drm/host/display_manager.h"
 #include "ui/ozone/platform/drm/host/drm_gpu_platform_support_host.h"
 
 namespace ui {
 
 namespace {
 
 typedef base::Callback<void(const base::FilePath&, base::File)>
     OnOpenDeviceReplyCallback;
 
 const char* kDisplayActionString[] = {
     "ADD",
     "REMOVE",
     "CHANGE",
 };
 
+bool Authenticate(int fd) {
+  drm_magic_t magic = 0;
+  // We need to make sure the DRM device has enough privilege. Use the DRM
+  // authentication logic to figure out if the device has enough permissions.
+  return !drmGetMagic(fd, &magic) && !drmAuthMagic(fd, magic);
+}
+
 base::File OpenDrmDevice(const base::FilePath& path) {
-  base::File file(path, base::File::FLAG_OPEN | base::File::FLAG_READ |
-                            base::File::FLAG_WRITE);
+  base::File file;
+  bool print_warning = true;
+  while (true) {
+    file = base::File(path, base::File::FLAG_OPEN | base::File::FLAG_READ |
+                                base::File::FLAG_WRITE);
 
-  base::File::Info info;
-  file.GetInfo(&info);
+    base::File::Info info;
+    file.GetInfo(&info);
 
-  CHECK(!info.is_directory);
-  CHECK(path.DirName() == base::FilePath("/dev/dri"));
+    CHECK(!info.is_directory);
+    CHECK(path.DirName() == base::FilePath("/dev/dri"));
 
-  if (!file.IsValid()) {
-    LOG(ERROR) << "Failed to open " << path.value() << ": "
-               << base::File::ErrorToString(file.error_details());
+    if (!file.IsValid()) {
+      LOG(ERROR) << "Failed to open " << path.value() << ": "
+                 << base::File::ErrorToString(file.error_details());
+      return file.Pass();
+    }
+
+    if (Authenticate(file.GetPlatformFile()))
+      break;
+
+    LOG_IF(WARNING, print_warning) << "Failed to authenticate " << path.value();
+
+    print_warning = false;
+    usleep(100000);
   }
 
+  VLOG(1) << "Succeeded authenticating " << path.value();
   return file.Pass();
 }
 
 void OpenDeviceOnWorkerThread(
     const base::FilePath& path,
     const scoped_refptr<base::TaskRunner>& reply_runner,
     const OnOpenDeviceReplyCallback& callback) {
   base::File file = OpenDrmDevice(path);
   reply_runner->PostTask(FROM_HERE,
                          base::Bind(callback, path, base::Passed(file.Pass())));
@@ skipping 247 matching lines @@
   FOR_EACH_OBSERVER(NativeDisplayObserver, observers_,
                     OnConfigurationChanged());
 }
 
 void DrmNativeDisplayDelegate::OnChannelEstablished(
     int host_id,
     scoped_refptr<base::SingleThreadTaskRunner> send_runner,
     const base::Callback<void(IPC::Message*)>& send_callback) {
   drm_devices_.clear();
   drm_devices_.insert(primary_graphics_card_path_);
+  {
+    // First device needs to be treated specially. We need to open this
+    // synchronously since the GPU process will need it to initialize the
+    // graphics state.
+    base::ThreadRestrictions::ScopedAllowIO allow_io;
+    base::File file = OpenDrmDevice(primary_graphics_card_path_);
+    if (!file.IsValid()) {
+      LOG(FATAL) << "Failed to open primary graphics card";
+      return;
+    }
+    OnAddGraphicsDevice(primary_graphics_card_path_, file.Pass());
+  }
+
   device_manager_->ScanDevices(this);
   FOR_EACH_OBSERVER(NativeDisplayObserver, observers_,
                     OnConfigurationChanged());
 }
 
 void DrmNativeDisplayDelegate::OnChannelDestroyed(int host_id) {
   // If the channel got destroyed in the middle of a configuration then just
   // respond with failure.
   if (!get_displays_callback_.is_null()) {
     base::ThreadTaskRunnerHandle::Get()->PostTask(
@@ skipping 48 matching lines @@
     configure_callback_map_.erase(it);
   }
 }
 
 void DrmNativeDisplayDelegate::RunUpdateDisplaysCallback(
     const GetDisplaysCallback& callback) const {
   callback.Run(displays_.get());
 }
 
 }  // namespace ui