feat: power down dGPUs on hybrid graphics laptops

kernel/src/Boot/Main.cpp

@@ -27,6 +27,7 @@
 #include <ACPI/AcpiEvents.hpp>
 #include <ACPI/EmbeddedController.hpp>
 #include <ACPI/Battery.hpp>
+#include <ACPI/AML/AmlParser.hpp>
 #include <Hal/Apic/ApicInit.hpp>
 #include <Pci/Pci.hpp>
 #include <Timekeeping/ApicTimer.hpp>
@@ -153,6 +154,12 @@ extern "C" void kmain() {
 
         Pci::Initialize(g_acpi.GetXSDT());
 
+        // _REG and _INI, once the EC and PCI config space (ECAM, for the
+        // extended registers PCI_Config regions reach) are both available:
+        // firmware settles which OS it is talking to here, and gates device
+        // power control on the answer.
+        Hal::AML::InitializeNamespaceObjects();
+
         Drivers::ProbeEarly();
         Drivers::InitializeGraphics();
 
@@ -162,6 +169,10 @@ extern "C" void kmain() {
         Drivers::PS2::Keyboard::Initialize();
         Drivers::PS2::Mouse::Initialize();
 
+        // Hybrid graphics: switch off a discrete GPU nothing drives before
+        // the normal probe can claim its USB-C/audio functions.
+        Drivers::PowerDownUnusedGpus();
+
         Drivers::ProbeNormal();
         Drivers::InitializeNetwork();
         Drivers::InitializeStorage();