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

ui/ozone/platform/dri/dri_wrapper.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/dri/dri_wrapper.h"
 
 #include <fcntl.h>
 #include <sys/mman.h>
 #include <unistd.h>
 #include <xf86drm.h>
@@ skipping 70 matching lines @@
 
 void HandlePageFlipEventOnUI(int fd,
                              unsigned int frame,
                              unsigned int seconds,
                              unsigned int useconds,
                              void* data) {
   scoped_ptr<PageFlipPayload> payload(static_cast<PageFlipPayload*>(data));
   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
     : public base::RefCountedThreadSafe<DriWrapper::IOWatcher>,
       public base::MessagePumpLibevent::Watcher {
  public:
   IOWatcher(int fd,
             const scoped_refptr<base::SingleThreadTaskRunner>& io_task_runner)
       : io_task_runner_(io_task_runner) {
     io_task_runner_->PostTask(FROM_HERE,
@@ skipping 55 matching lines @@
 
 DriWrapper::DriWrapper(const base::FilePath& device_path, base::File file)
     : device_path_(device_path), file_(file.Pass()) {
 }
 
 DriWrapper::~DriWrapper() {
   if (watcher_)
     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(
     const scoped_refptr<base::SingleThreadTaskRunner>& task_runner) {
   DCHECK(!task_runner_);
   task_runner_ = task_runner;
   watcher_ = new IOWatcher(file_.GetPlatformFile(), task_runner_);
 }
 
 ScopedDrmCrtcPtr DriWrapper::GetCrtc(uint32_t crtc_id) {
@@ skipping 226 matching lines @@
   DCHECK(file_.IsValid());
   return (drmSetMaster(file_.GetPlatformFile()) == 0);
 }
 
 bool DriWrapper::DropMaster() {
   DCHECK(file_.IsValid());
   return (drmDropMaster(file_.GetPlatformFile()) == 0);
 }
 
 }  // namespace ui