Don't use shadow buffer for system memory layers

There is no benefit at all to blit buffers that are already in local
memory. Add a check to avoid the useless blit.

Signed-off-by: Weifeng Liu <[email protected]>

Author: phreer

hwc2_device/HwcLayer.cpp

@@ -301,7 +301,8 @@ void HwcLayer::ImportFb() {
     is_pixel_blend_mode_supported = false;
 
   int kms_fd = parent_->GetPipe().device->GetFd();
-  bool use_shadow_fds = parent_->GetPipe().device->GetName() == "virtio_gpu" &&
+  bool use_shadow_fds = has_local_memory_flag(layer_data_.bi->usage) &&
+      parent_->GetPipe().device->GetName() == "virtio_gpu" &&
       !allow_p2p_ && (intel_dgpu_fd() >= 0) &&
       !virtio_gpu_allow_p2p(kms_fd) && InitializeBlitter(layer_data_.bi.value());
   layer_data_.bi->use_shadow_fds = use_shadow_fds;