ui/ozone: Flush CPU caches when mapping/unmapping prime pixmap

ui/ozone/platform/drm/common/client_native_pixmap_dmabuf.cc

Index: ui/ozone/platform/drm/common/client_native_pixmap_dmabuf.cc
diff --git a/ui/ozone/platform/drm/common/client_native_pixmap_dmabuf.cc b/ui/ozone/platform/drm/common/client_native_pixmap_dmabuf.cc
index 26d123a2a452209637a928aa78f7b07d1d1dd3a9..5b03eaf051ec6c78e83a452af05149b92877cb40 100644
--- a/ui/ozone/platform/drm/common/client_native_pixmap_dmabuf.cc
+++ b/ui/ozone/platform/drm/common/client_native_pixmap_dmabuf.cc
@@ -12,8 +12,46 @@
 #include "base/process/memory.h"
 #include "base/trace_event/trace_event.h"
 
+#if defined(OS_CHROMEOS)
+// TODO(vignatti): replace the local definitions below with #include
+// <linux/dma-buf.h> once kernel version 4.6 becomes widely used.
+#include <linux/types.h>
+
+struct local_dma_buf_sync {
+        __u64 flags;
+};
+
+#define LOCAL_DMA_BUF_SYNC_READ      (1 << 0)
+#define LOCAL_DMA_BUF_SYNC_WRITE     (2 << 0)
+#define LOCAL_DMA_BUF_SYNC_START     (0 << 2)
+#define LOCAL_DMA_BUF_SYNC_END       (1 << 2)
+
+#define LOCAL_DMA_BUF_BASE            'b'
+#define LOCAL_DMA_BUF_IOCTL_SYNC      _IOW(LOCAL_DMA_BUF_BASE, 0, struct local_dma_buf_sync)
+#endif
+
 namespace ui {
 
+namespace {
+
+void PrimeSyncStart(int dmabuf_fd) {
+  struct local_dma_buf_sync sync_start = {0};
+
+  sync_start.flags = LOCAL_DMA_BUF_SYNC_START | LOCAL_DMA_BUF_SYNC_READ;
+  if (drmIoctl(dmabuf_fd, LOCAL_DMA_BUF_IOCTL_SYNC, &sync_start))
+    PLOG(ERROR) << "Failed DMA_BUF_SYNC_START";
+}
+
+void PrimeSyncEnd(int dmabuf_fd) {
+  struct local_dma_buf_sync sync_end = {0};
+
+  sync_end.flags = LOCAL_DMA_BUF_SYNC_END | LOCAL_DMA_BUF_SYNC_WRITE;
+  if (drmIoctl(dmabuf_fd, LOCAL_DMA_BUF_IOCTL_SYNC, &sync_end))
+    PLOG(ERROR) << "Failed DMA_BUF_SYNC_END";
+}
+
+}  // namespace
+
 // static
 scoped_ptr<ClientNativePixmap> ClientNativePixmapDmaBuf::ImportFromDmabuf(
     int dmabuf_fd,
@@ -26,7 +64,7 @@ scoped_ptr<ClientNativePixmap> ClientNativePixmapDmaBuf::ImportFromDmabuf(
 ClientNativePixmapDmaBuf::ClientNativePixmapDmaBuf(int dmabuf_fd,
                                                    const gfx::Size& size,
                                                    int stride)
-    : size_(size), stride_(stride) {
+    : dmabuf_fd_(dmabuf_fd), size_(size), stride_(stride) {
   TRACE_EVENT0("drm", "ClientNativePixmapDmaBuf");
   size_t map_size = stride_ * size_.height();
   data_ = mmap(nullptr, map_size, (PROT_READ | PROT_WRITE), MAP_SHARED,
@@ -42,10 +80,15 @@ ClientNativePixmapDmaBuf::~ClientNativePixmapDmaBuf() {
 }
 
 void* ClientNativePixmapDmaBuf::Map() {
+  TRACE_EVENT0("drm", "DmaBuf:Map");
+  PrimeSyncStart(dmabuf_fd_.get());
   return data_;
 }
 
-void ClientNativePixmapDmaBuf::Unmap() {}
+void ClientNativePixmapDmaBuf::Unmap() {
+  TRACE_EVENT0("drm", "DmaBuf:Unmap");
+  PrimeSyncEnd(dmabuf_fd_.get());
+}
 
 void ClientNativePixmapDmaBuf::GetStride(int* stride) const {
   *stride = stride_;