[2/4]Allow hotplugging of primary DRM device

ui/ozone/platform/drm/gpu/drm_device.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/gpu/drm_device.h"
 
 #include <fcntl.h>
 #include <sys/mman.h>
 #include <unistd.h>
 #include <xf86drm.h>
@@ skipping 82 matching lines @@
 }
 
 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);
 }
 
-bool Authenticate(int fd) {
-  drm_magic_t magic;
-  memset(&magic, 0, sizeof(magic));
-  // 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);
-}
-
 }  // namespace
 
 class DrmDevice::IOWatcher
     : public base::RefCountedThreadSafe<DrmDevice::IOWatcher>,
       public base::MessagePumpLibevent::Watcher {
  public:
   IOWatcher(int fd,
             const scoped_refptr<base::SingleThreadTaskRunner>& io_task_runner)
       : io_task_runner_(io_task_runner), paused_(true), fd_(fd) {}
 
@@ skipping 84 matching lines @@
 }
 
 bool DrmDevice::Initialize() {
   // Ignore devices that cannot perform modesetting.
   if (!CanQueryForResources(file_.GetPlatformFile())) {
     VLOG(2) << "Cannot query for resources for '" << device_path_.value()
             << "'";
     return false;
   }
 
-  bool print_warning = true;
-  // TODO(dnicoara) Ugly hack to block until getting master. This is needed
-  // since DRM devices from an old GPU process may be getting deallocated while
-  // the new GPU process tries to take them.
-  // Move ownership of devices in the Browser process and just have the GPU
-  // processes authenticate.
-  while (!Authenticate(file_.GetPlatformFile())) {
-    PLOG_IF(WARNING, print_warning) << "Failed to take master on "
-                                    << device_path_.value();
-    print_warning = false;
-
-    usleep(100000);
-    file_ =
-        base::File(device_path_, base::File::FLAG_OPEN | base::File::FLAG_READ |
-                                     base::File::FLAG_WRITE);
-    LOG_IF(FATAL, !file_.IsValid())
-        << "Failed to open '" << device_path_.value()
-        << "': " << base::File::ErrorToString(file_.error_details());
-  }
-
-  VLOG(1) << "Succeeded in taking master on " << device_path_.value();
-
 #if defined(USE_DRM_ATOMIC)
   plane_manager_.reset(new HardwareDisplayPlaneManagerAtomic());
 #else
   plane_manager_.reset(new HardwareDisplayPlaneManagerLegacy());
 #endif  // defined(USE_DRM_ATOMIC)
   if (!plane_manager_->Initialize(this)) {
     LOG(ERROR) << "Failed to initialize the plane manager for "
                << device_path_.value();
     plane_manager_.reset();
     return false;
@@ skipping 253 matching lines @@
   DCHECK(file_.IsValid());
   return (drmSetMaster(file_.GetPlatformFile()) == 0);
 }
 
 bool DrmDevice::DropMaster() {
   DCHECK(file_.IsValid());
   return (drmDropMaster(file_.GetPlatformFile()) == 0);
 }
 
 }  // namespace ui