2 files changed, 30 insertions, 2 deletions
diff --git a/drm/resourcemanager.cpp b/drm/resourcemanager.cpp
index da1a2db..382a85a 100644
--- a/drm/resourcemanager.cpp
+++ b/drm/resourcemanager.cpp
@@ -20,6 +20,7 @@
 
 #include <cutils/properties.h>
 #include <log/log.h>
+#include <sys/stat.h>
 #include <sstream>
 #include <string>
 
@@ -32,7 +33,7 @@ int ResourceManager::Init() {
   char path_pattern[PROPERTY_VALUE_MAX];
   // Could be a valid path or it can have at the end of it the wildcard %
   // which means that it will try open all devices until an error is met.
-  int path_len = property_get("hwc.drm.device", path_pattern, "/dev/dri/card0");
+  int path_len = property_get("hwc.drm.device", path_pattern, "/dev/dri/card%");
   int ret = 0;
   if (path_pattern[path_len - 1] != '%') {
     ret = AddDrmDevice(std::string(path_pattern));
@@ -41,7 +42,13 @@ int ResourceManager::Init() {
     for (int idx = 0; !ret; ++idx) {
       std::ostringstream path;
       path << path_pattern << idx;
-      ret = AddDrmDevice(path.str());
+
+      struct stat buf;
+      if (stat(path.str().c_str(), &buf)) {
+        break;
+      } else if (IsKMSDev(path.str().c_str())) {
+        ret = AddDrmDevice(path.str());
+      }
     }
   }
 
@@ -94,6 +101,26 @@ DrmConnector *ResourceManager::AvailableWritebackConnector(int display) {
   return writeback_conn;
 }
 
+bool ResourceManager::IsKMSDev(const char *path) {
+  int fd = open(path, O_RDWR | O_CLOEXEC);
+  if (fd < 0)
+    return false;
+
+  auto res = drmModeGetResources(fd);
+  if (!res) {
+    close(fd);
+    return false;
+  }
+
+  bool is_kms = res->count_crtcs > 0 && res->count_connectors > 0 &&
+                res->count_encoders > 0;
+
+  drmModeFreeResources(res);
+  close(fd);
+
+  return is_kms;
+}
+
 DrmDevice *ResourceManager::GetDrmDevice(int display) {
   for (auto &drm : drms_) {
     if (drm->HandlesDisplay(display))
diff --git a/include/resourcemanager.h b/include/resourcemanager.h
index 7a86828..9fefb46 100644
--- a/include/resourcemanager.h
+++ b/include/resourcemanager.h
@@ -46,6 +46,7 @@ class ResourceManager {
 
  private:
   int AddDrmDevice(std::string path);
+  static bool IsKMSDev(const char *path);
 
   int num_displays_;
   std::vector<std::unique_ptr<DrmDevice>> drms_;