Skip encoder reprobing if no GPU changes have occurred

src/platform/common.h

@@ -558,6 +558,13 @@ namespace platf {
   std::vector<std::string>
   display_names(mem_type_e hwdevice_type);
 
+  /**
+   * @brief Returns if GPUs/drivers have changed since the last call to this function.
+   * @return `true` if a change has occurred or if it is unknown whether a change occurred.
+   */
+  bool
+  needs_encoder_reenumeration();
+
   boost::process::child
   run_command(bool elevated, bool interactive, const std::string &cmd, boost::filesystem::path &working_dir, const boost::process::environment &env, FILE *file, std::error_code &ec, boost::process::group *group);
 

src/platform/linux/misc.cpp

@@ -773,6 +773,16 @@ namespace platf {
     return {};
   }
 
+  /**
+   * @brief Returns if GPUs/drivers have changed since the last call to this function.
+   * @return `true` if a change has occurred or if it is unknown whether a change occurred.
+   */
+  bool
+  needs_encoder_reenumeration() {
+    // We don't track GPU state, so we will always reenumerate. Fortunately, it is fast on Linux.
+    return true;
+  }
+
   std::shared_ptr<display_t>
   display(mem_type_e hwdevice_type, const std::string &display_name, const video::config_t &config) {
 #ifdef SUNSHINE_BUILD_CUDA

src/platform/macos/display.mm

@@ -181,4 +181,14 @@ namespace platf {
 
     return display_names;
   }
+
+  /**
+   * @brief Returns if GPUs/drivers have changed since the last call to this function.
+   * @return `true` if a change has occurred or if it is unknown whether a change occurred.
+   */
+  bool
+  needs_encoder_reenumeration() {
+    // We don't track GPU state, so we will always reenumerate. Fortunately, it is fast on macOS.
+    return true;
+  }
 }  // namespace platf

src/platform/windows/display_base.cpp

@@ -1124,4 +1124,35 @@ namespace platf {
     return display_names;
   }
 
+  /**
+   * @brief Returns if GPUs/drivers have changed since the last call to this function.
+   * @return `true` if a change has occurred or if it is unknown whether a change occurred.
+   */
+  bool
+  needs_encoder_reenumeration() {
+    // Serialize access to the static DXGI factory
+    static std::mutex reenumeration_state_lock;
+    auto lg = std::lock_guard(reenumeration_state_lock);
+
+    // Keep a reference to the DXGI factory, which will keep track of changes internally.
+    static dxgi::factory1_t factory;
+    if (!factory || !factory->IsCurrent()) {
+      factory.reset();
+
+      auto status = CreateDXGIFactory1(IID_IDXGIFactory1, (void **) &factory);
+      if (FAILED(status)) {
+        BOOST_LOG(error) << "Failed to create DXGIFactory1 [0x"sv << util::hex(status).to_string_view() << ']';
+        factory.release();
+      }
+
+      // Always request reenumeration on the first streaming session just to ensure we
+      // can deal with any initialization races that may occur when the system is booting.
+      BOOST_LOG(info) << "Encoder reenumeration is required"sv;
+      return true;
+    }
+    else {
+      // The DXGI factory from last time is still current, so no encoder changes have occurred.
+      return false;
+    }
+  }
 }  // namespace platf