Workaround SDMA poll packet preemption.

Use async. signal handler to satisfy dependencies for SDMA blits.

Change-Id: Ifa8d3ee6810509f400a568ca2387ac6ab3ab7c36

runtime/hsa-runtime/core/inc/amd_blit_sdma.h

@@ -61,6 +61,7 @@ class BlitSdmaBase : public core::Blit {
   static const size_t kCopyPacketSize;
   static const size_t kMaxSingleCopySize;
   static const size_t kMaxSingleFillSize;
+  virtual bool isSDMA() const override { return true; }
 };
 
 // RingIndexTy: 32/64-bit monotonic ring index, counting in bytes.

runtime/hsa-runtime/core/inc/blit.h

@@ -113,6 +113,9 @@ class Blit {
   /// @return HSA_STATUS_SUCCESS if the request to enable/disable profiling is
   /// successful.
   virtual hsa_status_t EnableProfiling(bool enable) = 0;
+
+  /// @brief Blit operations use SDMA.
+  virtual bool isSDMA() const { return false; }
 };
 }  // namespace core