replace ad hoc driver loading with a proper driver manager, new DDK, new PnP manager with device matching, asynchronous startup, resource ownership and removal, add shared PCI capability helpers, replace typed, rigid services with a proper service manager, implement proper system shutdown and restart, shutting down unloads drivers and shuts down services, add simple power button, remove heavyweight boot self-tests and SMP stress runs, add monotonic timestamps to kernel debug output, fruitless USB and PS/2 fixes, make test builds opt in.

code/kernel/ke_display.c

@@ -1516,6 +1516,45 @@ DISPLAY_API KSTATUS KeDisplayRegisterDevice(DISPLAY_DEVICE* device) {
     return result;
 }
 
+DISPLAY_API KSTATUS KeDisplayUnregisterDevice(DISPLAY_DEVICE* device) {
+    if (!device || device == &gBootFbDevice)
+        return NTLSTATUS_INVALID_PARAMETER;
+
+    bool providerHeld = false;
+    KSTATUS status = KiDisplayAcquireProviderMutex(&providerHeld);
+    if (!KSUCCESS(status))
+        return status;
+
+    uintptr_t flags = KeAcquireSpinlock(&gDisplayLock);
+    DISPLAY_DEVICE** link = &gDisplayList;
+    while (*link && *link != device)
+        link = &(*link)->Next;
+
+    if (!*link) {
+        KeReleaseSpinlock(&gDisplayLock, flags);
+        KiDisplayReleaseProviderMutex(providerHeld);
+        return NTLSTATUS_NOT_FOUND;
+    }
+
+    *link = device->Next;
+    device->Next = (DISPLAY_DEVICE*)0;
+    if (gPrimaryDisplay == device) {
+        gPrimaryDisplay = (DISPLAY_DEVICE*)0;
+        gDisplayGeneration++;
+        gCursorDrawn = false;
+        gCursorUpdatePending = false;
+        gCursorAppliedGeneration = gCursorRequestGeneration;
+        gCursorCommittedX = DISPLAY_CURSOR_POS_INVALID;
+        gCursorCommittedY = DISPLAY_CURSOR_POS_INVALID;
+        gDirtyAll = false;
+        gDirtyRectCount = 0;
+        gDrawDepth = 0;
+    }
+    KeReleaseSpinlock(&gDisplayLock, flags);
+    KiDisplayReleaseProviderMutex(providerHeld);
+    return NTLSTATUS_SUCCESS;
+}
+
 // Implements the display Seed New Primary operation.
 static KSTATUS KiDisplaySeedNewPrimary(DISPLAY_DEVICE* oldDevice, DISPLAY_DEVICE* newDevice) {
     if (!oldDevice || !newDevice || oldDevice == newDevice)
@@ -1570,6 +1609,11 @@ DISPLAY_API KSTATUS KeDisplaySetPrimary(DISPLAY_DEVICE* device) {
 
     const char* name = device->Name ? device->Name : "?";
 
+    bool providerHeld = false;
+    KSTATUS result = KiDisplayAcquireProviderMutex(&providerHeld);
+    if (!KSUCCESS(result))
+        return result;
+
     uintptr_t flags = KeAcquireSpinlock(&gDisplayLock);
     bool found = false;
     for (DISPLAY_DEVICE* it = gDisplayList; it; it = it->Next) {
@@ -1580,6 +1624,7 @@ DISPLAY_API KSTATUS KeDisplaySetPrimary(DISPLAY_DEVICE* device) {
     }
     if (!found) {
         KeReleaseSpinlock(&gDisplayLock, flags);
+        KiDisplayReleaseProviderMutex(providerHeld);
         return NTLSTATUS_NOT_FOUND;
     }
 
@@ -1590,17 +1635,6 @@ DISPLAY_API KSTATUS KeDisplaySetPrimary(DISPLAY_DEVICE* device) {
     gCursorUpdatePending = gCursorVisible;
     KeReleaseSpinlock(&gDisplayLock, flags);
 
-    bool providerHeld = false;
-    KSTATUS result = KiDisplayAcquireProviderMutex(&providerHeld);
-    if (!KSUCCESS(result)) {
-        flags = KeAcquireSpinlock(&gDisplayLock);
-        gDisplayTransitionInProgress = false;
-        gDisplayGeneration++;
-        KeReleaseSpinlock(&gDisplayLock, flags);
-        KiDisplayQueueCursorWork();
-        return result;
-    }
-
     if (oldDevice && oldCursorDrawn && oldDevice->Ops && oldDevice->Ops->ShowCursor)
         (void)oldDevice->Ops->ShowCursor(oldDevice, false);