diff --git a/drmdevice.cpp b/drmdevice.cpp
index 7a54c9d..25273ac 100644
--- a/drmdevice.cpp
+++ b/drmdevice.cpp
@@ -96,6 +96,7 @@
     crtcs_.emplace_back(std::move(crtc));
   }
 
+  std::vector<int> possible_clones;
   for (int i = 0; !ret && i < res->count_encoders; ++i) {
     drmModeEncoderPtr e = drmModeGetEncoder(fd(), res->encoders[i]);
     if (!e) {
@@ -116,12 +117,18 @@
 
     std::unique_ptr<DrmEncoder> enc(
         new DrmEncoder(e, current_crtc, possible_crtcs));
-
+    possible_clones.push_back(e->possible_clones);
     drmModeFreeEncoder(e);
 
     encoders_.emplace_back(std::move(enc));
   }
 
+  for (unsigned int i = 0; i < encoders_.size(); i++) {
+    for (unsigned int j = 0; j < encoders_.size(); j++)
+      if (possible_clones[i] & (1 << j))
+        encoders_[i]->AddPossibleClone(encoders_[j].get());
+  }
+
   for (int i = 0; !ret && i < res->count_connectors; ++i) {
     drmModeConnectorPtr c = drmModeGetConnector(fd(), res->connectors[i]);
     if (!c) {
diff --git a/drmencoder.cpp b/drmencoder.cpp
index 6ae5d9a..277f9a4 100644
--- a/drmencoder.cpp
+++ b/drmencoder.cpp
@@ -39,6 +39,14 @@
   return crtc_;
 }
 
+bool DrmEncoder::CanClone(DrmEncoder *possible_clone) {
+  return possible_clones_.find(possible_clone) != possible_clones_.end();
+}
+
+void DrmEncoder::AddPossibleClone(DrmEncoder *possible_clone) {
+  possible_clones_.insert(possible_clone);
+}
+
 void DrmEncoder::set_crtc(DrmCrtc *crtc) {
   crtc_ = crtc;
   display_ = crtc->display();
diff --git a/drmencoder.h b/drmencoder.h
index aeab5ac..c99c36e 100644
--- a/drmencoder.h
+++ b/drmencoder.h
@@ -19,6 +19,7 @@
 
 #include "drmcrtc.h"
 
+#include <set>
 #include <stdint.h>
 #include <vector>
 #include <xf86drmMode.h>
@@ -42,6 +43,8 @@
   const std::vector<DrmCrtc *> &possible_crtcs() const {
     return possible_crtcs_;
   }
+  bool CanClone(DrmEncoder *encoder);
+  void AddPossibleClone(DrmEncoder *possible_clone);
 
  private:
   uint32_t id_;
@@ -49,6 +52,7 @@
   int display_;
 
   std::vector<DrmCrtc *> possible_crtcs_;
+  std::set<DrmEncoder *> possible_clones_;
 };
 }