3 files changed, 18 insertions, 2 deletions
diff --git a/system/OpenglSystemCommon/EmulatorFeatureInfo.h b/system/OpenglSystemCommon/EmulatorFeatureInfo.h
index f6d8ce59..a21b2576 100644
--- a/system/OpenglSystemCommon/EmulatorFeatureInfo.h
+++ b/system/OpenglSystemCommon/EmulatorFeatureInfo.h
@@ -133,6 +133,9 @@ static const char kSyncBufferData[] = "ANDROID_EMU_sync_buffer_data";
 // Batched descriptor set update
 static const char kVulkanBatchedDescriptorSetUpdate[] = "ANDROID_EMU_vulkan_batched_descriptor_set_update";
 
+// DMA for readback
+static const char kReadColorBufferDma[] = "ANDROID_EMU_read_color_buffer_dma";
+
 // Struct describing available emulator features
 struct EmulatorFeatureInfo {
 
@@ -159,7 +162,8 @@ struct EmulatorFeatureInfo {
         hasAsyncFrameCommands(false),
         hasVulkanQueueSubmitWithCommands(false),
         hasVulkanBatchedDescriptorSetUpdate(false),
-        hasSyncBufferData(false)
+        hasSyncBufferData(false),
+        hasReadColorBufferDma(false)
     { }
 
     SyncImpl syncImpl;
@@ -185,6 +189,7 @@ struct EmulatorFeatureInfo {
     bool hasVulkanQueueSubmitWithCommands;
     bool hasVulkanBatchedDescriptorSetUpdate;
     bool hasSyncBufferData;
+    bool hasReadColorBufferDma;
 };
 
 enum HostConnectionType {
diff --git a/system/OpenglSystemCommon/HostConnection.cpp b/system/OpenglSystemCommon/HostConnection.cpp
index 4afa20e7..8d15d086 100644
--- a/system/OpenglSystemCommon/HostConnection.cpp
+++ b/system/OpenglSystemCommon/HostConnection.cpp
@@ -672,6 +672,7 @@ ExtendedRCEncoderContext *HostConnection::rcEncoder()
         queryAndSetVulkanQueueSubmitWithCommandsSupport(rcEnc);
         queryAndSetVulkanBatchedDescriptorSetUpdateSupport(rcEnc);
         queryAndSetSyncBufferData(rcEnc);
+        queryAndSetReadColorBufferDma(rcEnc);
         queryVersion(rcEnc);
         if (m_processPipe) {
             m_processPipe->processPipeInit(m_connectionType, rcEnc);
@@ -971,6 +972,13 @@ void HostConnection::queryAndSetSyncBufferData(ExtendedRCEncoderContext* rcEnc)
     }
 }
 
+void HostConnection::queryAndSetReadColorBufferDma(ExtendedRCEncoderContext* rcEnc) {
+    std::string glExtensions = queryGLExtensions(rcEnc);
+    if (glExtensions.find(kReadColorBufferDma) != std::string::npos) {
+        rcEnc->featureInfo()->hasReadColorBufferDma = true;
+    }
+}
+
 GLint HostConnection::queryVersion(ExtendedRCEncoderContext* rcEnc) {
     GLint version = m_rcEnc->rcGetRendererVersion(m_rcEnc.get());
     return version;
diff --git a/system/OpenglSystemCommon/HostConnection.h b/system/OpenglSystemCommon/HostConnection.h
index 7c556290..31ca84cf 100644
--- a/system/OpenglSystemCommon/HostConnection.h
+++ b/system/OpenglSystemCommon/HostConnection.h
@@ -85,7 +85,9 @@ public:
     }
     virtual uint64_t lockAndWriteDma(void* data, uint32_t size) {
         if (m_dmaPtr && m_dmaPhysAddr) {
-            memcpy(m_dmaPtr, data, size);
+            if (data != m_dmaPtr) {
+                memcpy(m_dmaPtr, data, size);
+            }
             return m_dmaPhysAddr;
         } else if (m_dmaCxt) {
             return writeGoldfishDma(data, size, m_dmaCxt);
@@ -242,6 +244,7 @@ private:
     void queryAndSetVulkanQueueSubmitWithCommandsSupport(ExtendedRCEncoderContext *rcEnc);
     void queryAndSetVulkanBatchedDescriptorSetUpdateSupport(ExtendedRCEncoderContext *rcEnc);
     void queryAndSetSyncBufferData(ExtendedRCEncoderContext *rcEnc);
+    void queryAndSetReadColorBufferDma(ExtendedRCEncoderContext *rcEnc);
     GLint queryVersion(ExtendedRCEncoderContext* rcEnc);
 
 private: