Kernel: Add option to force using only the bootloader framebuffer

tomuta · linusg · commit 785c10fda9f2 · 2022-01-06T22:34:11.000+01:00
This allows forcing the use of only the framebuffer set up by the
bootloader and skips instantiating devices for any other graphics
cards that may be present.
diff --git a/Base/usr/share/man/man7/boot_parameters.md b/Base/usr/share/man/man7/boot_parameters.md
@@ -41,7 +41,7 @@ List of options:
   but only if **`acpi`** is set to **`limited`** or **`on`**, and a `MADT` (APIC) table is available.
   Otherwise, the kernel will fallback to use the i8259 PICs.
 
-* **`fbdev`** - This parameter expects **`on`** or **`off`**.
+* **`fbdev`** - This parameter expects one of the following values. **`on`**- Boot into the graphical environment (default). **`off`** - Boot into text mode. **`bootloader`** - Boot into the graphical environment, but only use the frame buffer set up by the bootloader and do not initialize any other graphics cards.
 
 * **`force_pio`** - If present on the command line, the IDE controllers will be force into PIO mode when initialized IDE Channels on boot.
 
diff --git a/Kernel/CommandLine.cpp b/Kernel/CommandLine.cpp
@@ -245,9 +245,14 @@ PanicMode CommandLine::panic_mode(Validate should_validate) const
     return PanicMode::Halt;
 }
 
-UNMAP_AFTER_INIT bool CommandLine::are_framebuffer_devices_enabled() const
-{
-    return lookup("fbdev"sv).value_or("on"sv) == "on"sv;
+UNMAP_AFTER_INIT auto CommandLine::are_framebuffer_devices_enabled() const -> FrameBufferDevices
+{
+    const auto fbdev_value = lookup("fbdev"sv).value_or("on"sv);
+    if (fbdev_value == "on"sv)
+        return FrameBufferDevices::Enabled;
+    if (fbdev_value == "bootloader"sv)
+        return FrameBufferDevices::BootloaderOnly;
+    return FrameBufferDevices::ConsoleOnly;
 }
 
 StringView CommandLine::userspace_init() const
diff --git a/Kernel/CommandLine.h b/Kernel/CommandLine.h
@@ -52,6 +52,12 @@ class CommandLine {
         No,
     };
 
+    enum class FrameBufferDevices {
+        Enabled,
+        ConsoleOnly,
+        BootloaderOnly
+    };
+
     [[nodiscard]] const String& string() const { return m_string; }
     Optional<StringView> lookup(StringView key) const;
     [[nodiscard]] bool contains(StringView key) const;
@@ -65,7 +71,7 @@ class CommandLine {
     [[nodiscard]] bool is_vmmouse_enabled() const;
     [[nodiscard]] PCIAccessLevel pci_access_level() const;
     [[nodiscard]] bool is_legacy_time_enabled() const;
-    [[nodiscard]] bool are_framebuffer_devices_enabled() const;
+    [[nodiscard]] FrameBufferDevices are_framebuffer_devices_enabled() const;
     [[nodiscard]] bool is_force_pio() const;
     [[nodiscard]] AcpiFeatureLevel acpi_feature_level() const;
     [[nodiscard]] StringView system_mode() const;
diff --git a/Kernel/Graphics/GraphicsManagement.cpp b/Kernel/Graphics/GraphicsManagement.cpp
@@ -36,9 +36,14 @@ UNMAP_AFTER_INIT GraphicsManagement::GraphicsManagement()
 {
 }
 
-bool GraphicsManagement::framebuffer_devices_allowed() const
+bool GraphicsManagement::framebuffer_devices_use_bootloader_framebuffer() const
 {
-    return kernel_command_line().are_framebuffer_devices_enabled();
+    return kernel_command_line().are_framebuffer_devices_enabled() == CommandLine::FrameBufferDevices::BootloaderOnly;
+}
+
+bool GraphicsManagement::framebuffer_devices_console_only() const
+{
+    return kernel_command_line().are_framebuffer_devices_enabled() == CommandLine::FrameBufferDevices::ConsoleOnly;
 }
 
 void GraphicsManagement::deactivate_graphical_mode()
@@ -73,60 +78,71 @@ UNMAP_AFTER_INIT bool GraphicsManagement::determine_and_initialize_graphics_devi
     VERIFY(is_vga_compatible_pci_device(device_identifier) || is_display_controller_pci_device(device_identifier));
     auto add_and_configure_adapter = [&](GenericGraphicsAdapter& graphics_device) {
         m_graphics_devices.append(graphics_device);
-        if (!framebuffer_devices_allowed()) {
+        if (framebuffer_devices_console_only()) {
             graphics_device.enable_consoles();
             return;
         }
         graphics_device.initialize_framebuffer_devices();
     };
 
     RefPtr<GenericGraphicsAdapter> adapter;
-    switch (device_identifier.hardware_id().vendor_id) {
-    case PCI::VendorID::QEMUOld:
-        if (device_identifier.hardware_id().device_id == 0x1111)
-            adapter = BochsGraphicsAdapter::initialize(device_identifier);
-        break;
-    case PCI::VendorID::VirtualBox:
-        if (device_identifier.hardware_id().device_id == 0xbeef)
-            adapter = BochsGraphicsAdapter::initialize(device_identifier);
-        break;
-    case PCI::VendorID::Intel:
-        adapter = IntelNativeGraphicsAdapter::initialize(device_identifier);
-        break;
-    case PCI::VendorID::VirtIO:
-        dmesgln("Graphics: Using VirtIO console");
-        adapter = Graphics::VirtIOGPU::GraphicsAdapter::initialize(device_identifier);
-        break;
-    default:
-        if (!is_vga_compatible_pci_device(device_identifier))
+
+    auto create_bootloader_framebuffer_device = [&]() {
+        if (multiboot_framebuffer_type == MULTIBOOT_FRAMEBUFFER_TYPE_RGB) {
+            dmesgln("Graphics: Using a preset resolution from the bootloader");
+            adapter = VGACompatibleAdapter::initialize_with_preset_resolution(device_identifier,
+                multiboot_framebuffer_addr,
+                multiboot_framebuffer_width,
+                multiboot_framebuffer_height,
+                multiboot_framebuffer_pitch);
+        }
+    };
+
+    if (framebuffer_devices_use_bootloader_framebuffer())
+        create_bootloader_framebuffer_device();
+
+    if (!adapter) {
+        switch (device_identifier.hardware_id().vendor_id) {
+        case PCI::VendorID::QEMUOld:
+            if (device_identifier.hardware_id().device_id == 0x1111)
+                adapter = BochsGraphicsAdapter::initialize(device_identifier);
+            break;
+        case PCI::VendorID::VirtualBox:
+            if (device_identifier.hardware_id().device_id == 0xbeef)
+                adapter = BochsGraphicsAdapter::initialize(device_identifier);
+            break;
+        case PCI::VendorID::Intel:
+            adapter = IntelNativeGraphicsAdapter::initialize(device_identifier);
             break;
-        // Note: Although technically possible that a system has a
-        // non-compatible VGA graphics device that was initialized by the
-        // Multiboot bootloader to provide a framebuffer, in practice we
-        // probably want to support these devices natively instead of
-        // initializing them as some sort of a generic GenericGraphicsAdapter. For now,
-        // the only known example of this sort of device is qxl in QEMU. For VGA
-        // compatible devices we don't have a special driver for (e.g. ati-vga,
-        // qxl-vga, cirrus-vga, vmware-svga in QEMU), it's much more likely that
-        // these devices will be supported by the Multiboot loader that will
-        // utilize VESA BIOS extensions (that we don't currently) of these cards
-        // support, so we want to utilize the provided framebuffer of these
-        // devices, if possible.
-        if (!m_vga_adapter && PCI::is_io_space_enabled(device_identifier.address())) {
-            if (multiboot_framebuffer_type == MULTIBOOT_FRAMEBUFFER_TYPE_RGB) {
-                dmesgln("Graphics: Using a preset resolution from the bootloader");
-                adapter = VGACompatibleAdapter::initialize_with_preset_resolution(device_identifier,
-                    multiboot_framebuffer_addr,
-                    multiboot_framebuffer_width,
-                    multiboot_framebuffer_height,
-                    multiboot_framebuffer_pitch);
+        case PCI::VendorID::VirtIO:
+            dmesgln("Graphics: Using VirtIO console");
+            adapter = Graphics::VirtIOGPU::GraphicsAdapter::initialize(device_identifier);
+            break;
+        default:
+            if (!is_vga_compatible_pci_device(device_identifier))
+                break;
+            //  Note: Although technically possible that a system has a
+            //  non-compatible VGA graphics device that was initialized by the
+            //  Multiboot bootloader to provide a framebuffer, in practice we
+            //  probably want to support these devices natively instead of
+            //  initializing them as some sort of a generic GenericGraphicsAdapter. For now,
+            //  the only known example of this sort of device is qxl in QEMU. For VGA
+            //  compatible devices we don't have a special driver for (e.g. ati-vga,
+            //  qxl-vga, cirrus-vga, vmware-svga in QEMU), it's much more likely that
+            //  these devices will be supported by the Multiboot loader that will
+            //  utilize VESA BIOS extensions (that we don't currently) of these cards
+            //  support, so we want to utilize the provided framebuffer of these
+            //  devices, if possible.
+            if (!m_vga_adapter && PCI::is_io_space_enabled(device_identifier.address())) {
+                create_bootloader_framebuffer_device();
+            } else {
+                dmesgln("Graphics: Using a VGA compatible generic adapter");
+                adapter = VGACompatibleAdapter::initialize(device_identifier);
             }
-        } else {
-            dmesgln("Graphics: Using a VGA compatible generic adapter");
-            adapter = VGACompatibleAdapter::initialize(device_identifier);
+            break;
         }
-        break;
     }
+
     if (!adapter)
         return false;
     add_and_configure_adapter(*adapter);
@@ -179,8 +195,10 @@ UNMAP_AFTER_INIT bool GraphicsManagement::initialize()
      * be created, so SystemServer will not try to initialize WindowServer.
      */
 
-    if (!framebuffer_devices_allowed())
-        dbgln("Forcing non-initialization of framebuffer devices");
+    if (framebuffer_devices_console_only())
+        dbgln("Forcing non-initialization of framebuffer devices (console only)");
+    else if (framebuffer_devices_use_bootloader_framebuffer())
+        dbgln("Forcing use of framebuffer set up by the bootloader");
 
     PCI::enumerate([&](PCI::DeviceIdentifier const& device_identifier) {
         // Note: Each graphics controller will try to set its native screen resolution
diff --git a/Kernel/Graphics/GraphicsManagement.h b/Kernel/Graphics/GraphicsManagement.h
@@ -36,7 +36,8 @@ class GraphicsManagement {
     unsigned allocate_minor_device_number() { return m_current_minor_number++; };
     GraphicsManagement();
 
-    bool framebuffer_devices_allowed() const;
+    bool framebuffer_devices_console_only() const;
+    bool framebuffer_devices_use_bootloader_framebuffer() const;
     bool framebuffer_devices_exist() const;
 
     Spinlock& main_vga_lock() { return m_main_vga_lock; }
