Verify automatic XInput mode switching

adapter_host_probe.cpp

@@ -18,13 +18,24 @@ namespace {
 
 constexpr uint32_t kXInputBootMagic = 0x58494e50; // "XINP"
 constexpr uint8_t kModeScratchRegister = 0;
+constexpr uint8_t kStatusRequest = 0x21;
+constexpr uint16_t kStatusIndex = 0x0005;
+uint8_t g_status_response[4]{};
 
 AdapterUsbMode g_mode = AdapterUsbMode::kSwitchProbe;
 AdapterHostProbeState g_probe;
+alarm_id_t g_reboot_alarm = 0;
 
 uint32_t now_ms() {
     return static_cast<uint32_t>(to_ms_since_boot(get_absolute_time()));
 }
+int64_t reboot_to_xinput(alarm_id_t alarm_id, void *user_data) {
+    (void)alarm_id;
+    (void)user_data;
+    watchdog_hw->scratch[kModeScratchRegister] = kXInputBootMagic;
+    watchdog_reboot(0, 0, 0);
+    return 0;
+}
 
 } // namespace
 
@@ -54,8 +65,24 @@ bool adapter_host_probe_vendor_control(uint8_t rhport, uint8_t stage,
     if (stage != CONTROL_STAGE_SETUP || request == nullptr ||
         request->bmRequestType_bit.direction != TUSB_DIR_IN ||
         request->bmRequestType_bit.type != TUSB_REQ_TYPE_VENDOR ||
-        request->bmRequestType_bit.recipient != TUSB_REQ_RCPT_DEVICE ||
-        request->bRequest != XInputFeasibility::kMsVendorRequest ||
+        request->bmRequestType_bit.recipient != TUSB_REQ_RCPT_DEVICE) {
+        return false;
+    }
+
+    if (request->bRequest == kStatusRequest &&
+        request->wIndex == kStatusIndex) {
+        const uint32_t current_time = now_ms();
+        g_status_response[0] =
+            g_mode == AdapterUsbMode::kXInput ? 1 : 0;
+        g_status_response[1] = g_probe.saw_ms_os_string() ? 1 : 0;
+        g_status_response[2] = g_probe.windows_confirmed() ? 1 : 0;
+        g_status_response[3] =
+            g_probe.should_reboot(current_time) ? 1 : 0;
+        return tud_control_xfer(rhport, request, g_status_response,
+                                sizeof(g_status_response));
+    }
+
+    if (request->bRequest != XInputFeasibility::kMsVendorRequest ||
         request->wIndex != XInputFeasibility::kMsCompatIdIndex) {
         return false;
     }
@@ -63,11 +90,19 @@ bool adapter_host_probe_vendor_control(uint8_t rhport, uint8_t stage,
     if (g_mode == AdapterUsbMode::kSwitchProbe) {
         g_probe.note_ms_compat_id_request(now_ms());
         PROBE_LOG("[HOST PROBE] Microsoft compatible-ID request confirmed\n");
-        return tud_control_xfer(
+        const bool queued = tud_control_xfer(
             rhport, request,
             const_cast<uint8_t *>(
                 XInputFeasibility::kProbeMsCompatIdDescriptor),
             sizeof(XInputFeasibility::kProbeMsCompatIdDescriptor));
+        if (queued && g_reboot_alarm == 0) {
+            g_reboot_alarm = add_alarm_in_ms(
+                AdapterHostProbeState::kRebootDelayMs,
+                reboot_to_xinput, nullptr, true);
+            PROBE_LOG("[HOST PROBE] XInput reboot alarm=%d\n",
+                      static_cast<int>(g_reboot_alarm));
+        }
+        return queued;
     }
 
     return tud_control_xfer(
@@ -75,13 +110,3 @@ bool adapter_host_probe_vendor_control(uint8_t rhport, uint8_t stage,
         const_cast<uint8_t *>(XInputFeasibility::kMsCompatIdDescriptor),
         sizeof(XInputFeasibility::kMsCompatIdDescriptor));
 }
-
-void adapter_host_probe_task() {
-    if (g_mode != AdapterUsbMode::kSwitchProbe ||
-        !g_probe.should_reboot(now_ms())) {
-        return;
-    }
-    watchdog_hw->scratch[kModeScratchRegister] = kXInputBootMagic;
-    PROBE_LOG("[HOST PROBE] rebooting once into XInput\n");
-    watchdog_reboot(0, 0, 10);
-}

adapter_host_probe.h

@@ -14,4 +14,3 @@ AdapterUsbMode adapter_host_probe_mode();
 void adapter_host_probe_note_string_descriptor(uint8_t index);
 bool adapter_host_probe_vendor_control(uint8_t rhport, uint8_t stage,
                                        tusb_control_request_t const *request);
-void adapter_host_probe_task();

adapter_host_probe_state.h

@@ -7,6 +7,7 @@ class AdapterHostProbeState {
     static constexpr uint32_t kRebootDelayMs = 100;
 
     void note_ms_os_string() { saw_ms_os_string_ = true; }
+    bool saw_ms_os_string() const { return saw_ms_os_string_; }
 
     void note_ms_compat_id_request(uint32_t now_ms) {
         if (!saw_ms_os_string_) {

switch-pico.cpp

@@ -278,9 +278,7 @@ int main() {
 
     while (true) {
         tud_task();          // USB device tasks
-#ifdef SWITCH_PICO_ADAPTER_FEASIBILITY
-        adapter_host_probe_task();
-#endif
+
 #ifdef SWITCH_PICO_BLUEPAD32
         switch (bootsel_pairing_button_task()) {
             case BootselPairingButtonEvent::kOpenPairing:

tests/xinput_feasibility_test.cpp

@@ -160,6 +160,8 @@ void test_host_probe_sequence() {
     expect(!state.windows_confirmed(),
            "compatible-ID request without signature confirmed Windows");
     state.note_ms_os_string();
+    expect(state.saw_ms_os_string(),
+           "Microsoft OS string observation was not retained");
     state.note_ms_compat_id_request(20);
     expect(state.windows_confirmed(),
            "two-stage Windows signature not confirmed");