feat(ui): add "Try Wake Host" button to no-signal overlay

internal/usbgadget/config.go

@@ -9,8 +9,9 @@ type gadgetConfigItem struct {
 	order       uint
 	device      string
 	path        []string
-	attrs       gadgetAttributes
-	configAttrs gadgetAttributes
+	attrs         gadgetAttributes
+	optionalAttrs gadgetAttributes // written with IgnoreErrors; for kernel features that may not exist
+	configAttrs   gadgetAttributes
 	configPath  []string
 	reportDesc  []byte
 }
@@ -34,7 +35,7 @@ var defaultGadgetConfig = map[string]gadgetConfigItem{
 			"bcdDevice": "0x0100", // USB2
 		},
 		configAttrs: gadgetAttributes{
-			"MaxPower":     "250",  // in unit of 2mA
+			"MaxPower":      "250", // in unit of 2mA
 			"bmAttributes": "0xa0", // bus-powered + remote wakeup
 		},
 	},

internal/usbgadget/config_tx.go

@@ -221,6 +221,16 @@ func (tx *UsbGadgetTransaction) writeGadgetItemConfig(item gadgetConfigItem, dep
 		)...)
 	}
 
+	if len(item.optionalAttrs) > 0 {
+		// write optional attributes (IgnoreErrors=true for backward compat with older kernels)
+		files = append(files, tx.writeGadgetAttrsOptional(
+			gadgetItemPath,
+			item.optionalAttrs,
+			component,
+			beforeChange,
+		)...)
+	}
+
 	// write report descriptor if available
 	reportDescPath := path.Join(gadgetItemPath, "report_desc")
 	if item.reportDesc != nil {
@@ -295,6 +305,24 @@ func (tx *UsbGadgetTransaction) writeGadgetAttrs(basePath string, attrs gadgetAt
 	return files
 }
 
+func (tx *UsbGadgetTransaction) writeGadgetAttrsOptional(basePath string, attrs gadgetAttributes, component string, beforeChange []string) (files []string) {
+	files = make([]string, 0)
+	for key, val := range attrs {
+		filePath := filepath.Join(basePath, key)
+		tx.addFileChange(component, RequestedFileChange{
+			Path:            filePath,
+			ExpectedState:   FileStateFileContentMatch,
+			ExpectedContent: []byte(val),
+			Description:     "write optional gadget attribute",
+			DependsOn:       []string{basePath},
+			BeforeChange:    beforeChange,
+			IgnoreErrors:    true,
+		})
+		files = append(files, filePath)
+	}
+	return files
+}
+
 func (tx *UsbGadgetTransaction) addReorderSymlinkChange(path string, target string, deps []string) {
 	tx.log.Trace().Str("path", path).Str("target", target).Msg("add reorder symlink change")
 

internal/usbgadget/hid_keyboard.go

@@ -23,6 +23,8 @@ var keyboardConfig = gadgetConfigItem{
 		"subclass":        "1",
 		"report_length":   "8",
 		"no_out_endpoint": "0",
+	},
+	optionalAttrs: gadgetAttributes{
 		"wakeup_on_write": "1",
 	},
 	reportDesc: keyboardReportDesc,

internal/usbgadget/hid_mouse_absolute.go

@@ -15,6 +15,8 @@ var absoluteMouseConfig = gadgetConfigItem{
 		"subclass":        "0",
 		"report_length":   "6",
 		"no_out_endpoint": "1",
+	},
+	optionalAttrs: gadgetAttributes{
 		"wakeup_on_write": "1",
 	},
 	reportDesc: absoluteMouseCombinedReportDesc,

internal/usbgadget/hid_mouse_relative.go

@@ -15,6 +15,8 @@ var relativeMouseConfig = gadgetConfigItem{
 		"subclass":        "1",
 		"report_length":   "5",
 		"no_out_endpoint": "1",
+	},
+	optionalAttrs: gadgetAttributes{
 		"wakeup_on_write": "1",
 	},
 	reportDesc: relativeMouseCombinedReportDesc,

ui/localization/messages/en.json

@@ -1093,5 +1093,8 @@
     "wake_on_lan_invalid_mac": "Invalid MAC address",
     "wake_on_lan_magic_sent_success": "Magic Packet sent successfully",
     "welcome_to_jetkvm": "Welcome to JetKVM",
-    "welcome_to_jetkvm_description": "Control any computer remotely"
+    "welcome_to_jetkvm_description": "Control any computer remotely",
+    "video_overlay_no_hdmi_try_wake": "If the target computer is sleeping, you can try waking it with a simulated keyboard press",
+    "video_overlay_no_hdmi_wake_host": "Try Wake Host",
+    "video_overlay_no_hdmi_wake_host_sending": "Sending wake signal..."
 }

ui/src/components/VideoOverlay.tsx

@@ -216,9 +216,11 @@ export function PeerConnectionDisconnectedOverlay({ show }: PeerConnectionDiscon
 interface HDMIErrorOverlayProps {
   readonly show: boolean;
   readonly hdmiState: string;
+  readonly onWakeHost?: () => void;
+  readonly isWaking?: boolean;
 }
 
-export function HDMIErrorOverlay({ show, hdmiState }: HDMIErrorOverlayProps) {
+export function HDMIErrorOverlay({ show, hdmiState, onWakeHost, isWaking }: HDMIErrorOverlayProps) {
   const isNoSignal = hdmiState === "no_signal";
   const isOtherError = hdmiState === "no_lock" || hdmiState === "out_of_range";
 
@@ -247,16 +249,30 @@ export function HDMIErrorOverlay({ show, hdmiState }: HDMIErrorOverlayProps) {
                         <li>{m.video_overlay_no_hdmi_ensure_cable()}</li>
                         <li>{m.video_overlay_no_hdmi_ensure_power()}</li>
                         <li>{m.video_overlay_no_hdmi_adapter_compat()}</li>
+                        <li>{m.video_overlay_no_hdmi_try_wake()}</li>
                       </ul>
                     </div>
-                    <div>
+                    <div className="flex items-center gap-x-2">
                       <LinkButton
                         to={"https://jetkvm.com/docs/getting-started/troubleshooting"}
                         theme="light"
                         text={m.video_overlay_learn_more()}
                         TrailingIcon={ArrowRightIcon}
                         size="SM"
                       />
+                      {onWakeHost && (
+                        <Button
+                          onClick={onWakeHost}
+                          text={
+                            isWaking
+                              ? m.video_overlay_no_hdmi_wake_host_sending()
+                              : m.video_overlay_no_hdmi_wake_host()
+                          }
+                          size="SM"
+                          theme="primary"
+                          disabled={isWaking}
+                        />
+                      )}
                     </div>
                   </div>
                 </div>

ui/src/components/WebRTCVideo.tsx

@@ -6,6 +6,7 @@ import { isWindows } from "@/utils";
 import useKeyboard from "@hooks/useKeyboard";
 import useMouse from "@hooks/useMouse";
 import { useRTCStore, useSettingsStore, useUiStore, useVideoStore } from "@hooks/stores";
+import { useJsonRpc } from "@hooks/useJsonRpc";
 import VirtualKeyboard from "@components/VirtualKeyboard";
 import Actionbar from "@components/ActionBar";
 import MacroBar from "@components/MacroBar";
@@ -30,6 +31,8 @@ export default function WebRTCVideo({
 }) {
   // Video and stream related refs and states
   const videoElm = useRef<HTMLVideoElement>(null);
+  const [isWaking, setIsWaking] = useState(false);
+  const { send } = useJsonRpc();
   const fullscreenContainerRef = useRef<HTMLDivElement>(null);
   const { mediaStream, peerConnectionState } = useRTCStore();
   const [isPlaying, setIsPlaying] = useState(false);
@@ -39,6 +42,18 @@ export default function WebRTCVideo({
   const isPointerLockPossible =
     window.location.protocol === "https:" || window.location.hostname === "localhost";
 
+  // Wake host handler - sends a spacebar press+release to wake sleeping host
+  const handleWakeHost = useCallback(() => {
+    setIsWaking(true);
+    // Send spacebar (HID usage 0x2C) press
+    send("keyboardReport", { keys: [0x2c, 0, 0, 0, 0, 0], modifier: 0 }, () => {
+      // Send key release
+      send("keyboardReport", { keys: [0, 0, 0, 0, 0, 0], modifier: 0 }, () => {
+        setTimeout(() => setIsWaking(false), 3000);
+      });
+    });
+  }, [send]);
+
   // Store hooks
   const settings = useSettingsStore();
   const { handleKeyPress, resetKeyboardState } = useKeyboard();
@@ -675,7 +690,12 @@ export default function WebRTCVideo({
                         >
                           <div className="relative h-full w-full rounded-md">
                             <LoadingVideoOverlay show={isVideoLoading} />
-                            <HDMIErrorOverlay show={hdmiError} hdmiState={hdmiState} />
+                            <HDMIErrorOverlay
+                              show={hdmiError}
+                              hdmiState={hdmiState}
+                              onWakeHost={handleWakeHost}
+                              isWaking={isWaking}
+                            />
                             <NoAutoplayPermissionsOverlay
                               show={hasNoAutoPlayPermissions}
                               onPlayClick={() => {