drm: GPU process manages VGEM fd.

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

Index: ui/ozone/platform/drm/host/drm_display_host_manager.cc
diff --git a/ui/ozone/platform/drm/host/drm_display_host_manager.cc b/ui/ozone/platform/drm/host/drm_display_host_manager.cc
index d22752717435b5d761cab96499d904cfab44477c..a062cef1bf4ee4ed70e6d0bf7e9abfbc13f3470e 100644
--- a/ui/ozone/platform/drm/host/drm_display_host_manager.cc
+++ b/ui/ozone/platform/drm/host/drm_display_host_manager.cc
@@ -8,6 +8,7 @@
 #include <stdio.h>
 #include <xf86drm.h>
 
+#include "base/files/file_enumerator.h"
 #include "base/logging.h"
 #include "base/strings/stringprintf.h"
 #include "base/thread_task_runner_handle.h"
@@ -31,6 +32,8 @@ typedef base::Callback<void(const base::FilePath&, scoped_ptr<DrmDeviceHandle>)>
     OnOpenDeviceReplyCallback;
 
 const char kDefaultGraphicsCardPattern[] = "/dev/dri/card%d";
+const char kVgemDevDriCardPath[] = "/dev/dri/";
+const char kVgemSysCardPath[] = "/sys/bus/platform/devices/vgem/drm/";
 
 const char* kDisplayActionString[] = {
     "ADD",
@@ -40,10 +43,11 @@ const char* kDisplayActionString[] = {
 
 void OpenDeviceOnWorkerThread(
     const base::FilePath& path,
+    bool is_vgem,
     const scoped_refptr<base::TaskRunner>& reply_runner,
     const OnOpenDeviceReplyCallback& callback) {
   scoped_ptr<DrmDeviceHandle> handle(new DrmDeviceHandle());
-  handle->Initialize(path);
+  handle->Initialize(path, is_vgem);
   reply_runner->PostTask(
       FROM_HERE, base::Bind(callback, path, base::Passed(handle.Pass())));
 }
@@ -75,6 +79,23 @@ base::FilePath GetPrimaryDisplayCardPath() {
   return base::FilePath();
 }
 
+base::FilePath GetVgemCardPath() {
+  base::FileEnumerator file_iter(
+      base::FilePath::FromUTF8Unsafe(kVgemSysCardPath), false,
+      base::FileEnumerator::DIRECTORIES, FILE_PATH_LITERAL("card*"));
+
+  while (!file_iter.Next().empty()) {
+    // Inspect the card%d directories in the directory and extract the filename.
+    std::string vgem_card_path =
+        kVgemDevDriCardPath +
+        file_iter.GetInfo().GetName().BaseName().MaybeAsASCII();
+    DVLOG(1) << "VGEM card path is " << vgem_card_path;
+    return base::FilePath(vgem_card_path);
+  }
+  DVLOG(1) << "Don't support VGEM";
+  return base::FilePath();
+}
+
 class FindDisplaySnapshotById {
  public:
   FindDisplaySnapshotById(int64_t display_id) : display_id_(display_id) {}
@@ -104,11 +125,14 @@ DrmDisplayHostManager::DrmDisplayHostManager(DrmGpuPlatformSupportHost* proxy,
     // graphics state.
     base::ThreadRestrictions::ScopedAllowIO allow_io;
     primary_drm_device_handle_.reset(new DrmDeviceHandle());
-    if (!primary_drm_device_handle_->Initialize(primary_graphics_card_path_)) {
+    if (!primary_drm_device_handle_->Initialize(primary_graphics_card_path_,
+                                                false)) {
       LOG(FATAL) << "Failed to open primary graphics card";
       return;
     }
     drm_devices_.insert(primary_graphics_card_path_);
+
+    vgem_card_path_ = GetVgemCardPath();
   }
 
   device_manager_->AddObserver(this);
@@ -233,6 +257,7 @@ void DrmDisplayHostManager::ProcessEvent() {
           task_pending_ = base::WorkerPool::PostTask(
               FROM_HERE,
               base::Bind(&OpenDeviceOnWorkerThread, event.path,
+                         event.path == vgem_card_path_,
                          base::ThreadTaskRunnerHandle::Get(),
                          base::Bind(&DrmDisplayHostManager::OnAddGraphicsDevice,
                                     weak_ptr_factory_.GetWeakPtr())),
@@ -248,6 +273,7 @@ void DrmDisplayHostManager::ProcessEvent() {
       case DeviceEvent::REMOVE:
         DCHECK(event.path != primary_graphics_card_path_)
             << "Removing primary graphics card";
+        DCHECK(event.path != vgem_card_path_) << "Removing VGEM device";
         auto it = drm_devices_.find(event.path);
         if (it != drm_devices_.end()) {
           task_pending_ = base::ThreadTaskRunnerHandle::Get()->PostTask(
@@ -266,8 +292,13 @@ void DrmDisplayHostManager::OnAddGraphicsDevice(
     scoped_ptr<DrmDeviceHandle> handle) {
   if (handle->IsValid()) {
     drm_devices_.insert(path);
-    proxy_->Send(new OzoneGpuMsg_AddGraphicsDevice(
-        path, base::FileDescriptor(handle->PassFD())));
+    if (handle->IsVgem()) {
+      proxy_->Send(new OzoneGpuMsg_AddVgemDevice(
+          path, base::FileDescriptor(handle->PassFD())));
+    } else {
+      proxy_->Send(new OzoneGpuMsg_AddGraphicsDevice(
+          path, base::FileDescriptor(handle->PassFD())));
+    }
     NotifyDisplayDelegate();
   }
 
@@ -298,7 +329,7 @@ void DrmDisplayHostManager::OnChannelEstablished(
   if (!handle) {
     base::ThreadRestrictions::ScopedAllowIO allow_io;
     handle.reset(new DrmDeviceHandle());
-    if (!handle->Initialize(primary_graphics_card_path_))
+    if (!handle->Initialize(primary_graphics_card_path_, false))
       LOG(FATAL) << "Failed to open primary graphics card";
   }