Allow NVENC to be forced to try capturing non-Nvidia GPUs

src/platform/linux/kmsgrab.cpp

@@ -625,10 +625,13 @@ namespace platf {
           }
 
           // Skip non-Nvidia cards if we're looking for CUDA devices
+          // unless NVENC is selected manually by the user
           if (mem_type == mem_type_e::cuda && !card.is_nvidia()) {
             BOOST_LOG(debug) << file << " is not a CUDA device"sv;
+            if (config::video.encoder != "nvenc") {
               continue;
             }
+          }
 
           auto end = std::end(card);
           for (auto plane = std::begin(card); plane != end; ++plane) {
@@ -1635,10 +1638,16 @@ namespace platf {
       }
 
       // Skip non-Nvidia cards if we're looking for CUDA devices
+      // unless NVENC is selected manually by the user
       if (hwdevice_type == mem_type_e::cuda && !card.is_nvidia()) {
         BOOST_LOG(debug) << file << " is not a CUDA device"sv;
+        if (config::video.encoder == "nvenc") {
+          BOOST_LOG(warning) << "Using NVENC with your display connected to a different GPU may not work properly!"sv;
+        }
+        else {
           continue;
         }
+      }
 
       auto crtc_to_monitor = kms::map_crtc_to_monitor(card.monitors(conn_type_count));