feat(linux): use connector name as default display name on linux

docs/configuration.md

@@ -948,7 +948,8 @@ editing the `conf` file in a text editor. Use the examples as reference.
             Info: Detected display: DP-1 (id: 3) connected: false
             Info: Detected display: DVI-D-1 (id: 4) connected: false
             @endcode
-            You need to use the id value inside the parenthesis, e.g. `1`.
+            It is recommended to use the stable display connector name (text right before the parenthesis, e.g. DP-0) for this value.
+            For wlgrab/x11grab and kmsgrab the numeric id value can also be used.
             <br>
             <br>
             **macOS:**

src/platform/linux/kmsgrab.cpp

@@ -6,6 +6,7 @@
 #include <errno.h>
 #include <fcntl.h>
 #include <filesystem>
+#include <ranges>
 #include <thread>
 #include <unistd.h>
 
@@ -848,6 +849,38 @@ namespace platf {
       BOOST_LOG(debug) << ss.str();
     }
 
+    /**
+     * @brief Map display name to monitor index
+     *
+     * @param display_name Name of the display to determine monitor index for (or monitor index string value)
+     * @return monitor's display index
+     */
+    static int64_t map_display_name_to_monitor_index(const std::string_view &display_name) {
+      // Handle (legacy) monitor index strings by converting them to integer
+      if (display_name.empty() || std::ranges::all_of(display_name, ::isdigit)) {
+        return util::from_view(display_name);
+      }
+      // display_name is a connector name (not empty and containing non-digits) try to resolve correct monitor index like correlate_wayland does
+      auto index_begin = display_name.find_last_of('-');
+      std::int64_t index;
+      if (index_begin == std::string_view::npos) {
+        index = 1;
+      } else {
+        index = std::max<int64_t>(1, util::from_view(display_name.substr(index_begin + 1)));
+      }
+      auto type = kms::from_view(display_name.substr(0, index_begin));
+      for (auto &card_descriptor : kms::card_descriptors) {
+        for (const auto &monitor_descriptor : card_descriptor.crtc_to_monitor | std::views::values) {
+          if (monitor_descriptor.type == type && monitor_descriptor.index == index) {
+            BOOST_LOG(debug) << "Mapped '"sv << display_name << "' to a monitor index " << monitor_descriptor.monitor_index;
+            return monitor_descriptor.monitor_index;
+          }
+        }
+      }
+      BOOST_LOG(warning) << "Couldn't map '"sv << display_name << "' to a monitor index. Falling back to first monitor in list (index=0).";
+      return 0;  // Fallback to first index if nothing can be matched
+    }
+
     /**
      * @brief Base KMS display capture backend shared by RAM and VRAM paths.
      */
@@ -873,7 +906,7 @@ namespace platf {
       int init(const std::string &display_name, const ::video::config_t &config) {
         delay = ::video::capture_frame_interval(config);
 
-        int monitor_index = util::from_view(display_name);
+        int monitor_index = map_display_name_to_monitor_index(display_name);
         int monitor = 0;
 
         fs::path card_dir {"/dev/dri"sv};
@@ -2099,8 +2132,8 @@ namespace platf {
         kms::env_height = std::max(kms::env_height, (int) (crtc->y + crtc->height));
 
         kms::print(plane.get(), fb.get(), crtc.get());
-
-        display_names.emplace_back(std::to_string(count++));
+        display_names.emplace_back(std::format("{}-{}", drmModeGetConnectorTypeName(it->second.type), it->second.index));
+        count++;
       }
 
       cds.emplace_back(kms::card_descriptor_t {

src/platform/linux/x11grab.cpp

@@ -4,6 +4,7 @@
  */
 // standard includes
 #include <fstream>
+#include <ranges>
 #include <thread>
 
 // plaform includes
@@ -506,47 +507,41 @@ namespace platf {
       refresh();
 
       int streamedMonitor = -1;
-      if (!display_name.empty()) {
+      if (!display_name.empty() && std::ranges::all_of(display_name, ::isdigit)) {
+        // Resolve (legacy) monitor index from display_name
         streamedMonitor = (int) util::from_view(display_name);
       }
 
-      if (streamedMonitor != -1) {
-        BOOST_LOG(info) << "Configuring selected display ("sv << streamedMonitor << ") to stream"sv;
-        screen_res_t screenr {x11::rr::GetScreenResources(xdisplay.get(), xwindow)};
-        int output = screenr->noutput;
-
-        output_info_t result;
-        int monitor = 0;
-        for (int x = 0; x < output; ++x) {
-          output_info_t out_info {x11::rr::GetOutputInfo(xdisplay.get(), screenr.get(), screenr->outputs[x])};
-          if (out_info) {
-            if (monitor++ == streamedMonitor) {
-              result = std::move(out_info);
-              break;
-            }
+      screen_res_t screenr {x11::rr::GetScreenResources(xdisplay.get(), xwindow)};
+      int output = screenr->noutput;
+
+      output_info_t result;
+      bool result_found = false;
+      int monitor = 0;
+      for (int x = 0; x < output; ++x) {
+        output_info_t out_info {x11::rr::GetOutputInfo(xdisplay.get(), screenr.get(), screenr->outputs[x])};
+        if (out_info) {
+          // Match monitor by index if a valid one is present, otherwise try to resolve by matching output name to display_name
+          if ((streamedMonitor >= 0 && monitor == streamedMonitor) || (streamedMonitor < 0 && out_info->name == display_name)) {
+            result = std::move(out_info);
+            result_found = true;
+            break;
           }
+          monitor++;
         }
+      }
 
-        if (!result) {
-          BOOST_LOG(error) << "Could not stream display number ["sv << streamedMonitor << "], there are only ["sv << monitor << "] displays."sv;
-          return -1;
-        }
-
-        if (result->crtc) {
-          crtc_info_t crt_info {x11::rr::GetCrtcInfo(xdisplay.get(), screenr.get(), result->crtc)};
-          BOOST_LOG(info)
-            << "Streaming display: "sv << result->name << " with res "sv << crt_info->width << 'x' << crt_info->height << " offset by "sv << crt_info->x << 'x' << crt_info->y;
+      if (result_found && result->crtc) {
+        crtc_info_t crt_info {x11::rr::GetCrtcInfo(xdisplay.get(), screenr.get(), result->crtc)};
+        BOOST_LOG(info)
+          << "Streaming display: "sv << result->name << " with res "sv << crt_info->width << 'x' << crt_info->height << " offset by "sv << crt_info->x << 'x' << crt_info->y;
 
-          width = crt_info->width;
-          height = crt_info->height;
-          offset_x = crt_info->x;
-          offset_y = crt_info->y;
-        } else {
-          BOOST_LOG(warning) << "Couldn't get requested display info, defaulting to recording entire virtual desktop"sv;
-          width = xattr.width;
-          height = xattr.height;
-        }
+        width = crt_info->width;
+        height = crt_info->height;
+        offset_x = crt_info->x;
+        offset_y = crt_info->y;
       } else {
+        BOOST_LOG(warning) << "Couldn't get info for requested display ["sv << display_name << "], defaulting to recording entire virtual desktop"sv;
         width = xattr.width;
         height = xattr.height;
       }
@@ -971,22 +966,16 @@ namespace platf {
     screen_res_t screenr {x11::rr::GetScreenResources(xdisplay.get(), xwindow)};
     int output = screenr->noutput;
 
+    std::vector<std::string> names;
     int monitor = 0;
     for (int x = 0; x < output; ++x) {
       output_info_t out_info {x11::rr::GetOutputInfo(xdisplay.get(), screenr.get(), screenr->outputs[x])};
       if (out_info) {
-        BOOST_LOG(info) << "Detected display: "sv << out_info->name << " (id: "sv << monitor << ")"sv << out_info->name << " connected: "sv << (out_info->connection == RR_Connected);
-        ++monitor;
+        BOOST_LOG(info) << "Detected display: "sv << out_info->name << " (id: "sv << monitor++ << ")"sv << out_info->name << " connected: "sv << (out_info->connection == RR_Connected);
+        names.emplace_back(out_info->name);
       }
     }
 
-    std::vector<std::string> names;
-    names.reserve(monitor);
-
-    for (auto x = 0; x < monitor; ++x) {
-      names.emplace_back(std::to_string(x));
-    }
-
     return names;
   }
 

src_assets/common/assets/web/configs/tabs/audiovideo/DisplayOutputSelector.vue

@@ -9,7 +9,13 @@ const props = defineProps([
 ])
 
 const config = ref(props.config)
-const outputNamePlaceholder = (props.platform === 'windows') ? '{de9bb7e2-186e-505b-9e93-f48793333810}' : '0'
+let _outputNamePlaceholder = '0';
+if(props.platform === 'windows') {
+  _outputNamePlaceholder = '{de9bb7e2-186e-505b-9e93-f48793333810}';
+} else if(props.platform === 'linux' || props.platform === 'freebsd') {
+  _outputNamePlaceholder = 'DP-0';
+}
+const outputNamePlaceholder = _outputNamePlaceholder;  // NOSONAR(javascript:S1481,javascript:S1854): Constant used by vue.js binding for placeholder below
 </script>
 
 <template>
@@ -33,21 +39,19 @@ const outputNamePlaceholder = (props.platform === 'windows') ? '{de9bb7e2-186e-5
         <template #freebsd>
           <pre style="white-space: pre-line;">
             Info: Detecting displays
-            Info: Detected display: DVI-D-0 (id: 0) connected: false
-            Info: Detected display: HDMI-0 (id: 1) connected: true
-            Info: Detected display: DP-0 (id: 2) connected: true
-            Info: Detected display: DP-1 (id: 3) connected: false
-            Info: Detected display: DVI-D-1 (id: 4) connected: false
+            Info: Detected display: HDMI-A-1 connected: true
+            Info: Detected display: DP-1 connected: true
+            Info: Detected display: DP-2 connected: false
+            Info: Detected display: DVI-D-3 connected: false
           </pre>
         </template>
         <template #linux>
           <pre style="white-space: pre-line;">
             Info: Detecting displays
-            Info: Detected display: DVI-D-0 (id: 0) connected: false
-            Info: Detected display: HDMI-0 (id: 1) connected: true
-            Info: Detected display: DP-0 (id: 2) connected: true
-            Info: Detected display: DP-1 (id: 3) connected: false
-            Info: Detected display: DVI-D-1 (id: 4) connected: false
+            Info: Detected display: HDMI-A-1 connected: true
+            Info: Detected display: DP-1 connected: true
+            Info: Detected display: DP-2 connected: false
+            Info: Detected display: DVI-D-3 connected: false
           </pre>
         </template>
         <template #macos>

src_assets/common/assets/web/public/assets/locale/en.json

@@ -333,7 +333,8 @@
     "origin_web_ui_allowed_pc": "Only localhost may access Web UI",
     "origin_web_ui_allowed_wan": "Anyone may access Web UI",
     "output_name": "Display Id",
-    "output_name_desc_unix": "During Sunshine startup, you should see the list of detected displays. Note: You need to use the id value inside the parenthesis. Below is an example; the actual output can be found in the Troubleshooting tab.",
+    "output_name_desc_macos": "During Sunshine startup, you should see the list of detected displays. Note: You need to use the id value inside the parenthesis. Below is an example; the actual output can be found in the Troubleshooting tab.",
+    "output_name_desc_unix": "During Sunshine startup, you should see the list of detected displays. Note: It is recommended to use the display's connector name (e.g. DP-0) but depending on the capture backend used other values may be possible (see documentation for details). Below is an example; the actual output can be found in the Troubleshooting tab.",
     "output_name_desc_windows": "Manually specify a display device id to use for capture. If unset, the primary display is captured. Note: If you specified a GPU above, this display must be connected to that GPU. During Sunshine startup, you should see the list of detected displays. Below is an example; the actual output can be found in the Troubleshooting tab.",
     "packetsize": "Packet Size Limit",
     "packetsize_desc": "Limit the packet size to avoid fragmentation on a low MTU link. This helps reduce packet loss and micro-stuttering, while streaming over a layer 2 VPN to clients that cannot configure this value, e.g. Moonlight for Android/iOS. Reduce the bitrate when using low values. Values larger than 1456 require jumbo frames. Range: 0, 200-65535. A value of 0 will disable the limit.",