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_dpc.c

@@ -13,6 +13,9 @@ static SPINLOCK      gDpcLock;
 static volatile int32_t gDpcInitialized = 0;
 static volatile int32_t gDpcActive      = 0;
 
+// Bound a single interrupt-exit dispatch so self-requeuing devices yield the CPU.
+#define KE_DPC_DISPATCH_BUDGET 64u
+
 // Initializes dpc System.
 void KeInitializeDpcSystem(void) {
     LIST_INIT(&gDpcQueue);
@@ -83,7 +86,10 @@ void KiDrainDpcQueue(void) {
     if (oldIrql < DISPATCH_LEVEL)
         KeRaiseIrql(DISPATCH_LEVEL);
 
-    while (true) {
+    // The xHCI event routine already bounds its own work, but an IRQ stream
+    // can requeue it after every dispatch. Limit the whole drain, too. The
+    // pending queue is picked up at the next timer or device interrupt exit.
+    for (uint32_t dispatched = 0; dispatched < KE_DPC_DISPATCH_BUDGET; dispatched++) {
         uintptr_t flags = KeAcquireSpinlock(&gDpcLock);
         LIST_ENTRY* node = KeListPopHeadChecked(&gDpcQueue);
         if (!node) {