From d64d03e0d6e0543ca70f422c7fab0aa61c5963b0 Mon Sep 17 00:00:00 2001
From: Hendiadyoin1 <leon.a@serenityos.org>
Date: Mon, 11 Sep 2023 18:28:30 +0200
Subject: [PATCH] Kernel: Make Graphics device detection a bit more idomatic

---
 Kernel/Bus/PCI/Definitions.h      | 10 ++++++++++
 Kernel/Devices/GPU/Management.cpp |  6 +++---
 2 files changed, 13 insertions(+), 3 deletions(-)

diff --git a/Kernel/Bus/PCI/Definitions.h b/Kernel/Bus/PCI/Definitions.h
index cdbe15a62d..c1a2c025f8 100644
--- a/Kernel/Bus/PCI/Definitions.h
+++ b/Kernel/Bus/PCI/Definitions.h
@@ -93,6 +93,7 @@ static constexpr u16 msix_control_enable = 0x8000;
 
 // Taken from https://pcisig.com/sites/default/files/files/PCI_Code-ID_r_1_11__v24_Jan_2019.pdf
 enum class ClassID {
+    Legacy = 0x00,
     MassStorage = 0x01,
     Network = 0x02,
     Display = 0x03,
@@ -114,6 +115,14 @@ enum class ClassID {
     NonEssentialInstrumentation = 0x13,
 };
 
+namespace Legacy {
+
+enum class SubclassID {
+    Any = 0x00,
+    VGACompatible = 0x01
+};
+
+}
 namespace MassStorage {
 
 enum class SubclassID {
@@ -336,6 +345,7 @@ AK_TYPEDEF_DISTINCT_ORDERED_ID(u8, ClassCode);
 AK_MAKE_DISTINCT_NUMERIC_COMPARABLE_TO_ENUM(ClassCode, ClassID)
 
 AK_TYPEDEF_DISTINCT_ORDERED_ID(u8, SubclassCode);
+AK_MAKE_DISTINCT_NUMERIC_COMPARABLE_TO_ENUM(SubclassCode, Legacy::SubclassID);
 AK_MAKE_DISTINCT_NUMERIC_COMPARABLE_TO_ENUM(SubclassCode, MassStorage::SubclassID);
 AK_MAKE_DISTINCT_NUMERIC_COMPARABLE_TO_ENUM(SubclassCode, Network::SubclassID);
 AK_MAKE_DISTINCT_NUMERIC_COMPARABLE_TO_ENUM(SubclassCode, Display::SubclassID);
diff --git a/Kernel/Devices/GPU/Management.cpp b/Kernel/Devices/GPU/Management.cpp
index 32e24031b0..0f83960522 100644
--- a/Kernel/Devices/GPU/Management.cpp
+++ b/Kernel/Devices/GPU/Management.cpp
@@ -110,14 +110,14 @@ static inline bool is_vga_compatible_pci_device(PCI::DeviceIdentifier const& dev
 {
     // Note: Check for Display Controller, VGA Compatible Controller or
     // Unclassified, VGA-Compatible Unclassified Device
-    auto is_display_controller_vga_compatible = device_identifier.class_code().value() == 0x3 && device_identifier.subclass_code().value() == 0x0;
-    auto is_general_pci_vga_compatible = device_identifier.class_code().value() == 0x0 && device_identifier.subclass_code().value() == 0x1;
+    auto is_display_controller_vga_compatible = device_identifier.class_code() == PCI::ClassID::Display && device_identifier.subclass_code() == PCI::Display::SubclassID::VGA;
+    auto is_general_pci_vga_compatible = device_identifier.class_code() == PCI::ClassID::Legacy && device_identifier.subclass_code() == PCI::Legacy::SubclassID::VGACompatible;
     return is_display_controller_vga_compatible || is_general_pci_vga_compatible;
 }
 
 static inline bool is_display_controller_pci_device(PCI::DeviceIdentifier const& device_identifier)
 {
-    return device_identifier.class_code().value() == 0x3;
+    return device_identifier.class_code() == PCI::ClassID::Display;
 }
 
 struct PCIGraphicsDriverInitializer {