DisplaySettings+WindowServer: Add support for display connector devices

12 files changed, 309 insertions, 39 deletions

diff --git a/Kernel/API/FB.h b/Kernel/API/FB.h
index ad929082d3..339f32eb41 100644
--- a/Kernel/API/FB.h
+++ b/Kernel/API/FB.h
@@ -18,11 +18,13 @@ ALWAYS_INLINE int fb_get_properties(int fd, FBProperties* info)
     return ioctl(fd, FB_IOCTL_GET_PROPERTIES, info);
 }
 
+// FIXME: Remove this once framebuffer devices are removed.
 ALWAYS_INLINE int fb_get_head_properties(int fd, FBHeadProperties* info)
 {
     return ioctl(fd, FB_IOCTL_GET_HEAD_PROPERTIES, info);
 }
 
+// FIXME: Remove this once framebuffer devices are removed.
 ALWAYS_INLINE int fb_get_resolution(int fd, FBHeadResolution* info)
 {
     FBHeadProperties head_properties;
@@ -36,6 +38,7 @@ ALWAYS_INLINE int fb_get_resolution(int fd, FBHeadResolution* info)
     return 0;
 }
 
+// FIXME: Remove this once framebuffer devices are removed.
 ALWAYS_INLINE int fb_set_resolution(int fd, FBHeadResolution* info)
 {
     return ioctl(fd, FB_IOCTL_SET_HEAD_RESOLUTION, info);
@@ -56,6 +59,31 @@ ALWAYS_INLINE int fb_set_head_vertical_offset_buffer(int fd, FBHeadVerticalOffse
     return ioctl(fd, FB_IOCTL_SET_HEAD_VERTICAL_OFFSET_BUFFER, vertical_offset);
 }
 
+ALWAYS_INLINE int fb_set_head_mode_setting(int fd, FBHeadModeSetting* mode_setting)
+{
+    return ioctl(fd, FB_IOCTL_SET_HEAD_MODE_SETTING, mode_setting);
+}
+
+ALWAYS_INLINE int fb_get_head_mode_setting(int fd, FBHeadModeSetting* mode_setting)
+{
+    FBHeadModeSetting head_mode_setting;
+    if (auto rc = ioctl(fd, FB_IOCTL_GET_HEAD_MODE_SETTING, &head_mode_setting); rc < 0)
+        return rc;
+    mode_setting->horizontal_stride = head_mode_setting.horizontal_stride;
+    mode_setting->pixel_clock_in_khz = head_mode_setting.pixel_clock_in_khz;
+    mode_setting->horizontal_active = head_mode_setting.horizontal_active;
+    mode_setting->horizontal_front_porch_pixels = head_mode_setting.horizontal_front_porch_pixels;
+    mode_setting->horizontal_sync_time_pixels = head_mode_setting.horizontal_sync_time_pixels;
+    mode_setting->horizontal_blank_pixels = head_mode_setting.horizontal_blank_pixels;
+    mode_setting->vertical_active = head_mode_setting.vertical_active;
+    mode_setting->vertical_front_porch_lines = head_mode_setting.vertical_front_porch_lines;
+    mode_setting->vertical_sync_time_lines = head_mode_setting.vertical_sync_time_lines;
+    mode_setting->vertical_blank_lines = head_mode_setting.vertical_blank_lines;
+    mode_setting->horizontal_offset = head_mode_setting.horizontal_offset;
+    mode_setting->vertical_offset = head_mode_setting.vertical_offset;
+    return 0;
+}
+
 ALWAYS_INLINE int fb_flush_buffers(int fd, int index, FBRect const* rects, unsigned count)
 {
     FBFlushRects fb_flush_rects;
diff --git a/Userland/Applications/DisplaySettings/MonitorSettingsWidget.cpp b/Userland/Applications/DisplaySettings/MonitorSettingsWidget.cpp
index 7d384a1b59..eec77d796b 100644
--- a/Userland/Applications/DisplaySettings/MonitorSettingsWidget.cpp
+++ b/Userland/Applications/DisplaySettings/MonitorSettingsWidget.cpp
@@ -148,7 +148,8 @@ void MonitorSettingsWidget::load_current_settings()
     size_t virtual_screen_count = 0;
     for (size_t i = 0; i < m_screen_layout.screens.size(); i++) {
         String screen_display_name;
-        if (m_screen_layout.screens[i].mode == WindowServer::ScreenLayout::Screen::Mode::Device) {
+        if (m_screen_layout.screens[i].mode == WindowServer::ScreenLayout::Screen::Mode::Device
+            || m_screen_layout.screens[i].mode == WindowServer::ScreenLayout::Screen::Mode::DisplayConnectorDevice) {
             if (auto edid = EDID::Parser::from_framebuffer_device(m_screen_layout.screens[i].device.value(), 0); !edid.is_error()) { // TODO: multihead
                 screen_display_name = display_name_from_edid(edid.value());
                 m_screen_edids.append(edid.release_value());
diff --git a/Userland/Libraries/LibC/sys/ioctl_numbers.h b/Userland/Libraries/LibC/sys/ioctl_numbers.h
index 95e8b74742..417afc3dea 100644
--- a/Userland/Libraries/LibC/sys/ioctl_numbers.h
+++ b/Userland/Libraries/LibC/sys/ioctl_numbers.h
@@ -26,6 +26,7 @@ struct FBProperties {
     unsigned char refresh_rate_support;
 };
 
+// FIXME: Remove this once framebuffer devices are removed.
 struct FBHeadProperties {
     int head_index;
 
@@ -52,6 +53,7 @@ struct FBHeadModeSetting {
     int vertical_offset;
 };
 
+// FIXME: Remove this once framebuffer devices are removed.
 struct FBHeadResolution {
     int head_index;
     int pitch;
@@ -181,6 +183,9 @@ enum IOCtlNumber {
 #define FB_IOCTL_GET_HEAD_VERTICAL_OFFSET_BUFFER FB_IOCTL_GET_HEAD_VERTICAL_OFFSET_BUFFER
 #define FB_IOCTL_FLUSH_HEAD_BUFFERS FB_IOCTL_FLUSH_HEAD_BUFFERS
 #define FB_IOCTL_FLUSH_HEAD FB_IOCTL_FLUSH_HEAD
+#define FB_IOCTL_SET_HEAD_MODE_SETTING FB_IOCTL_SET_HEAD_MODE_SETTING
+#define FB_IOCTL_GET_HEAD_MODE_SETTING FB_IOCTL_GET_HEAD_MODE_SETTING
+#define FB_IOCTL_SET_SAFE_HEAD_MODE_SETTING FB_IOCTL_SET_SAFE_HEAD_MODE_SETTING
 #define KEYBOARD_IOCTL_GET_NUM_LOCK KEYBOARD_IOCTL_GET_NUM_LOCK
 #define KEYBOARD_IOCTL_SET_NUM_LOCK KEYBOARD_IOCTL_SET_NUM_LOCK
 #define KEYBOARD_IOCTL_GET_CAPS_LOCK KEYBOARD_IOCTL_GET_CAPS_LOCK
diff --git a/Userland/Services/WindowServer/Compositor.cpp b/Userland/Services/WindowServer/Compositor.cpp
index 926472dd6f..6941a5c6ca 100644
--- a/Userland/Services/WindowServer/Compositor.cpp
+++ b/Userland/Services/WindowServer/Compositor.cpp
@@ -721,6 +721,13 @@ void Compositor::flush(Screen& screen)
         // now so that they can be sent to the device.
         screen.flush_display(screen_data.m_buffers_are_flipped ? 1 : 0);
     }
+
+    // Note: We write all contents from the internal buffer of WindowServer Screen
+    // to the actual framebuffer with the write() syscall, but after we flush the screen
+    // to ensure we are in a "clean state"...
+    // FIXME: This write is completely inefficient and needs to be done in chunks
+    // only when appropriate...
+    screen.write_all_display_contents();
 }
 
 void Compositor::invalidate_screen()
diff --git a/Userland/Services/WindowServer/HardwareScreenBackend.cpp b/Userland/Services/WindowServer/HardwareScreenBackend.cpp
index 2c25dd8253..36469a5cd6 100644
--- a/Userland/Services/WindowServer/HardwareScreenBackend.cpp
+++ b/Userland/Services/WindowServer/HardwareScreenBackend.cpp
@@ -17,8 +17,9 @@
 
 namespace WindowServer {
 
-HardwareScreenBackend::HardwareScreenBackend(String device)
+HardwareScreenBackend::HardwareScreenBackend(String device, bool display_connector_device_backed)
     : m_device(move(device))
+    , display_connector_device_backed(display_connector_device_backed)
 {
 }
 
@@ -42,7 +43,10 @@ HardwareScreenBackend::~HardwareScreenBackend()
         m_framebuffer_fd = -1;
     }
     if (m_framebuffer) {
-        MUST(Core::System::munmap(m_framebuffer, m_size_in_bytes));
+        if (!display_connector_device_backed)
+            MUST(Core::System::munmap(m_framebuffer, m_size_in_bytes));
+        else
+            free(m_framebuffer);
 
         m_framebuffer = nullptr;
         m_size_in_bytes = 0;
@@ -51,41 +55,95 @@ HardwareScreenBackend::~HardwareScreenBackend()
 
 ErrorOr<void> HardwareScreenBackend::set_head_resolution(FBHeadResolution resolution)
 {
-    auto rc = fb_set_resolution(m_framebuffer_fd, &resolution);
-    if (rc != 0)
-        return Error::from_syscall("fb_set_resolution", rc);
+    if (!display_connector_device_backed) {
+        auto rc = fb_set_resolution(m_framebuffer_fd, &resolution);
+        if (rc != 0)
+            return Error::from_syscall("fb_set_resolution", rc);
+    } else {
+        FBHeadModeSetting mode_setting;
+        memset(&mode_setting, 0, sizeof(FBHeadModeSetting));
+        mode_setting.horizontal_active = resolution.width;
+        mode_setting.vertical_active = resolution.height;
+        mode_setting.horizontal_stride = resolution.pitch;
+        auto rc = fb_set_head_mode_setting(m_framebuffer_fd, &mode_setting);
+        if (rc != 0)
+            return Error::from_syscall("fb_set_head_mode_setting", rc);
+    }
+
     return {};
 }
 
 ErrorOr<void> HardwareScreenBackend::unmap_framebuffer()
 {
     if (m_framebuffer) {
-        size_t previous_size_in_bytes = m_size_in_bytes;
-        return Core::System::munmap(m_framebuffer, previous_size_in_bytes);
+        if (!display_connector_device_backed) {
+            size_t previous_size_in_bytes = m_size_in_bytes;
+            return Core::System::munmap(m_framebuffer, previous_size_in_bytes);
+        } else {
+            free(m_framebuffer);
+        }
     }
     return {};
 }
 
-ErrorOr<void> HardwareScreenBackend::map_framebuffer()
+ErrorOr<void> HardwareScreenBackend::write_all_contents(Gfx::IntRect const& virtual_rect)
 {
-    FBHeadProperties properties;
-    properties.head_index = 0;
-    int rc = fb_get_head_properties(m_framebuffer_fd, &properties);
-    if (rc != 0)
-        return Error::from_syscall("fb_get_head_properties", rc);
-    m_size_in_bytes = properties.buffer_length;
+    if (!display_connector_device_backed)
+        return {};
+    lseek(m_framebuffer_fd, 0, SEEK_SET);
+    write(m_framebuffer_fd, scanline(0, 0), virtual_rect.height() * m_pitch);
+    if (m_can_set_head_buffer) {
+        if (lseek(m_framebuffer_fd, virtual_rect.height() * m_pitch, SEEK_SET) < 0) {
+            VERIFY_NOT_REACHED();
+        }
 
-    m_framebuffer = (Gfx::ARGB32*)TRY(Core::System::mmap(nullptr, m_size_in_bytes, PROT_READ | PROT_WRITE, MAP_SHARED, m_framebuffer_fd, 0));
+        if (write(m_framebuffer_fd, scanline(0, 0), virtual_rect.height() * m_pitch) < 0)
+            VERIFY_NOT_REACHED();
+    }
+    return {};
+}
 
-    if (m_can_set_head_buffer) {
-        // Note: fall back to assuming the second buffer starts right after the last line of the first
-        // Note: for now, this calculation works quite well, so need to defer it to another function
-        // that does ioctl to figure out the correct offset. If a Framebuffer device ever happens to
-        // to set the second buffer at different location than this, we might need to consider bringing
-        // back a function with ioctl to check this.
-        m_back_buffer_offset = static_cast<size_t>(properties.pitch) * properties.height;
+ErrorOr<void> HardwareScreenBackend::map_framebuffer()
+{
+    if (!display_connector_device_backed) {
+        FBHeadProperties properties;
+        properties.head_index = 0;
+        int rc = fb_get_head_properties(m_framebuffer_fd, &properties);
+        if (rc != 0)
+            return Error::from_syscall("fb_get_head_properties", rc);
+        m_size_in_bytes = properties.buffer_length;
+
+        m_framebuffer = (Gfx::ARGB32*)TRY(Core::System::mmap(nullptr, m_size_in_bytes, PROT_READ | PROT_WRITE, MAP_SHARED, m_framebuffer_fd, 0));
+
+        if (m_can_set_head_buffer) {
+            // Note: fall back to assuming the second buffer starts right after the last line of the first
+            // Note: for now, this calculation works quite well, so need to defer it to another function
+            // that does ioctl to figure out the correct offset. If a Framebuffer device ever happens to
+            // to set the second buffer at different location than this, we might need to consider bringing
+            // back a function with ioctl to check this.
+            m_back_buffer_offset = static_cast<size_t>(properties.pitch) * properties.height;
+        } else {
+            m_back_buffer_offset = 0;
+        }
     } else {
-        m_back_buffer_offset = 0;
+        FBHeadModeSetting mode_setting {};
+        memset(&mode_setting, 0, sizeof(FBHeadModeSetting));
+        int rc = fb_get_head_mode_setting(m_framebuffer_fd, &mode_setting);
+        if (rc != 0) {
+            return Error::from_syscall("fb_get_head_mode_setting", rc);
+        }
+        m_size_in_bytes = mode_setting.horizontal_stride * mode_setting.vertical_active * 2;
+        m_framebuffer = (Gfx::ARGB32*)malloc(m_size_in_bytes);
+        if (m_can_set_head_buffer) {
+            // Note: fall back to assuming the second buffer starts right after the last line of the first
+            // Note: for now, this calculation works quite well, so need to defer it to another function
+            // that does ioctl to figure out the correct offset. If a Framebuffer device ever happens to
+            // to set the second buffer at different location than this, we might need to consider bringing
+            // back a function with ioctl to check this.
+            m_back_buffer_offset = static_cast<size_t>(mode_setting.horizontal_stride) * mode_setting.vertical_active;
+        } else {
+            m_back_buffer_offset = 0;
+        }
     }
 
     return {};
@@ -93,13 +151,34 @@ ErrorOr<void> HardwareScreenBackend::map_framebuffer()
 
 ErrorOr<FBHeadProperties> HardwareScreenBackend::get_head_properties()
 {
-    FBHeadProperties properties;
-    properties.head_index = 0;
-    int rc = fb_get_head_properties(m_framebuffer_fd, &properties);
-    if (rc != 0)
-        return Error::from_syscall("fb_get_head_properties", rc);
-    m_pitch = static_cast<int>(properties.pitch);
-    return properties;
+    if (!display_connector_device_backed) {
+        FBHeadProperties properties;
+        properties.head_index = 0;
+        int rc = fb_get_head_properties(m_framebuffer_fd, &properties);
+        if (rc != 0)
+            return Error::from_syscall("fb_get_head_properties", rc);
+        m_pitch = static_cast<int>(properties.pitch);
+        return properties;
+    } else {
+        FBHeadModeSetting mode_setting {};
+        memset(&mode_setting, 0, sizeof(FBHeadModeSetting));
+        int rc = fb_get_head_mode_setting(m_framebuffer_fd, &mode_setting);
+        if (rc != 0) {
+            return Error::from_syscall("fb_get_head_mode_setting", rc);
+        }
+        m_pitch = mode_setting.horizontal_stride;
+        // Note: We translate (for now, until Framebuffer devices are removed) the FBHeadModeSetting
+        // structure to FBHeadProperties.
+        FBHeadProperties properties;
+        properties.head_index = 0;
+        properties.pitch = mode_setting.horizontal_stride;
+        properties.width = mode_setting.horizontal_active;
+        properties.height = mode_setting.vertical_active;
+        properties.offset = 0;
+        properties.buffer_length = mode_setting.horizontal_stride * mode_setting.vertical_active * 2;
+        return properties;
+    }
+    VERIFY_NOT_REACHED();
 }
 
 void HardwareScreenBackend::set_head_buffer(int head_index)
diff --git a/Userland/Services/WindowServer/HardwareScreenBackend.h b/Userland/Services/WindowServer/HardwareScreenBackend.h
index c491db7f8b..e1ce874ea2 100644
--- a/Userland/Services/WindowServer/HardwareScreenBackend.h
+++ b/Userland/Services/WindowServer/HardwareScreenBackend.h
@@ -18,7 +18,7 @@ class HardwareScreenBackend : public ScreenBackend {
 public:
     virtual ~HardwareScreenBackend();
 
-    HardwareScreenBackend(String device);
+    HardwareScreenBackend(String device, bool display_connector_device_backed);
 
     virtual ErrorOr<void> open() override;
 
@@ -32,8 +32,17 @@ public:
     virtual ErrorOr<void> set_head_resolution(FBHeadResolution) override;
     virtual ErrorOr<FBHeadProperties> get_head_properties() override;
 
+    virtual ErrorOr<void> write_all_contents(Gfx::IntRect const&) override;
+
     String m_device {};
     int m_framebuffer_fd { -1 };
+    bool const display_connector_device_backed { false };
+
+    Gfx::ARGB32* scanline(int buffer_index, int y) const
+    {
+        size_t buffer_offset = buffer_index == 1 ? m_back_buffer_offset : 0;
+        return reinterpret_cast<Gfx::ARGB32*>(((u8*)m_framebuffer) + buffer_offset + (y * m_pitch));
+    }
 };
 
 }
diff --git a/Userland/Services/WindowServer/Screen.cpp b/Userland/Services/WindowServer/Screen.cpp
index 710cfab10f..ef6b24165a 100644
--- a/Userland/Services/WindowServer/Screen.cpp
+++ b/Userland/Services/WindowServer/Screen.cpp
@@ -231,7 +231,7 @@ bool Screen::open_device()
 
     switch (info.mode) {
     case ScreenLayout::Screen::Mode::Device: {
-        m_backend = make<HardwareScreenBackend>(info.device.value());
+        m_backend = make<HardwareScreenBackend>(info.device.value(), false);
         auto return_value = m_backend->open();
         if (return_value.is_error()) {
             dbgln("Screen #{}: Failed to open backend: {}", index(), return_value.error());
@@ -241,6 +241,17 @@ bool Screen::open_device()
         set_resolution(true);
         return true;
     }
+    case ScreenLayout::Screen::Mode::DisplayConnectorDevice: {
+        m_backend = make<HardwareScreenBackend>(info.device.value(), true);
+        auto return_value = m_backend->open();
+        if (return_value.is_error()) {
+            dbgln("Screen #{}: Failed to open display connector backend: {}", index(), return_value.error());
+            return false;
+        }
+
+        set_resolution(true);
+        return true;
+    }
     case ScreenLayout::Screen::Mode::Virtual: {
         m_backend = make<VirtualScreenBackend>();
         // Virtual device open should never fail.
@@ -539,6 +550,11 @@ void Screen::flush_display(int buffer_index)
     flush_rects.pending_flush_rects.clear_with_capacity();
 }
 
+void Screen::write_all_display_contents()
+{
+    MUST(m_backend->write_all_contents(m_virtual_rect));
+}
+
 void Screen::flush_display_front_buffer(int front_buffer_index, Gfx::IntRect& rect)
 {
     VERIFY(m_backend->m_can_device_flush_buffers);
diff --git a/Userland/Services/WindowServer/Screen.h b/Userland/Services/WindowServer/Screen.h
index 44f1510d8c..8737a92eae 100644
--- a/Userland/Services/WindowServer/Screen.h
+++ b/Userland/Services/WindowServer/Screen.h
@@ -174,6 +174,8 @@ public:
 
     CompositorScreenData& compositor_screen_data() { return *m_compositor_screen_data; }
 
+    void write_all_display_contents();
+
 private:
     Screen(size_t);
     bool open_device();
diff --git a/Userland/Services/WindowServer/ScreenBackend.h b/Userland/Services/WindowServer/ScreenBackend.h
index 2b6de0f3f0..4e96bd7f2f 100644
--- a/Userland/Services/WindowServer/ScreenBackend.h
+++ b/Userland/Services/WindowServer/ScreenBackend.h
@@ -34,6 +34,8 @@ public:
     virtual ErrorOr<void> set_head_resolution(FBHeadResolution) = 0;
     virtual ErrorOr<FBHeadProperties> get_head_properties() = 0;
 
+    virtual ErrorOr<void> write_all_contents(Gfx::IntRect const&) { return {}; }
+
     bool m_can_device_flush_buffers { true };
     bool m_can_set_head_buffer { false };
 
diff --git a/Userland/Services/WindowServer/ScreenLayout.h b/Userland/Services/WindowServer/ScreenLayout.h
index 5fb3eddee8..039a7d48c2 100644
--- a/Userland/Services/WindowServer/ScreenLayout.h
+++ b/Userland/Services/WindowServer/ScreenLayout.h
@@ -21,6 +21,7 @@ public:
         enum class Mode {
             Invalid,
             Device,
+            DisplayConnectorDevice,
             Virtual,
         } mode;
         Optional<String> device;
@@ -42,6 +43,7 @@ public:
             switch (mode) {
                 __ENUMERATE_MODE_ENUM(Invalid)
                 __ENUMERATE_MODE_ENUM(Device)
+                __ENUMERATE_MODE_ENUM(DisplayConnectorDevice)
                 __ENUMERATE_MODE_ENUM(Virtual)
             }
             VERIFY_NOT_REACHED();
@@ -59,7 +61,9 @@ public:
     bool normalize();
     bool load_config(Core::ConfigFile const& config_file, String* error_msg = nullptr);
     bool save_config(Core::ConfigFile& config_file, bool sync = true) const;
+    // FIXME: Remove this once framebuffer devices are removed.
     bool try_auto_add_framebuffer(String const&);
+    bool try_auto_add_display_connector(String const&);
 
     // TODO: spaceship operator
     bool operator!=(ScreenLayout const& other) const;
diff --git a/Userland/Services/WindowServer/ScreenLayout.ipp b/Userland/Services/WindowServer/ScreenLayout.ipp
index 2c8d8b4b87..3d5f32f1cd 100644
--- a/Userland/Services/WindowServer/ScreenLayout.ipp
+++ b/Userland/Services/WindowServer/ScreenLayout.ipp
@@ -236,8 +236,15 @@ bool ScreenLayout::load_config(const Core::ConfigFile& config_file, String* erro
         if (!config_file.has_group(group_name))
             break;
         auto str_mode = config_file.read_entry(group_name, "Mode");
-        auto mode = str_mode == "Device" ? Screen::Mode::Device : str_mode == "Virtual" ? Screen::Mode::Virtual
-                                                                                        : Screen::Mode::Invalid;
+        Screen::Mode mode { Screen::Mode::Invalid };
+        if (str_mode == "Device") {
+            mode = Screen::Mode::Device;
+        } else if (str_mode == "DisplayConnectorDevice") {
+            mode = Screen::Mode::DisplayConnectorDevice;
+        } else if (str_mode == "Virtual") {
+            mode = Screen::Mode::Virtual;
+        }
+
         if (mode == Screen::Mode::Invalid) {
             *error_msg = String::formatted("Invalid screen mode '{}'", str_mode);
             *this = {};
@@ -302,6 +309,90 @@ bool ScreenLayout::operator!=(const ScreenLayout& other) const
     return false;
 }
 
+bool ScreenLayout::try_auto_add_display_connector(String const& device_path)
+{
+    int display_connector_fd = open(device_path.characters(), O_RDWR | O_CLOEXEC);
+    if (display_connector_fd < 0) {
+        int err = errno;
+        dbgln("Error ({}) opening display connector device {}", err, device_path);
+        return false;
+    }
+    ScopeGuard fd_guard([&] {
+        close(display_connector_fd);
+    });
+
+    FBHeadModeSetting mode_setting {};
+    memset(&mode_setting, 0, sizeof(FBHeadModeSetting));
+    if (fb_get_head_mode_setting(display_connector_fd, &mode_setting) < 0) {
+        int err = errno;
+        dbgln("Error ({}) querying resolution from display connector device {}", err, device_path);
+        return false;
+    }
+    if (mode_setting.horizontal_active == 0 || mode_setting.vertical_active == 0) {
+        // Looks like the display is not turned on. Since we don't know what the desired
+        // resolution should be, use the main display as reference.
+        if (screens.is_empty())
+            return false;
+        auto& main_screen = screens[main_screen_index];
+        mode_setting.horizontal_active = main_screen.resolution.width();
+        mode_setting.vertical_active = main_screen.resolution.height();
+    }
+
+    auto append_screen = [&](Gfx::IntRect const& new_screen_rect) {
+        screens.append({ .mode = Screen::Mode::DisplayConnectorDevice,
+            .device = device_path,
+            .location = new_screen_rect.location(),
+            .resolution = new_screen_rect.size(),
+            .scale_factor = 1 });
+    };
+
+    if (screens.is_empty()) {
+        append_screen({ 0, 0, mode_setting.horizontal_active, mode_setting.vertical_active });
+        return true;
+    }
+
+    auto original_screens = move(screens);
+    screens = original_screens;
+    ArmedScopeGuard screens_guard([&] {
+        screens = move(original_screens);
+    });
+
+    // Now that we know the current resolution, try to find a location that we can add onto
+    // TODO: make this a little more sophisticated in case a more complex layout is already configured
+    for (auto& screen : screens) {
+        auto screen_rect = screen.virtual_rect();
+        Gfx::IntRect new_screen_rect {
+            screen_rect.right() + 1,
+            screen_rect.top(),
+            (int)mode_setting.horizontal_active,
+            (int)mode_setting.vertical_active
+        };
+
+        bool collision = false;
+        for (auto& other_screen : screens) {
+            if (&screen == &other_screen)
+                continue;
+            if (other_screen.virtual_rect().intersects(new_screen_rect)) {
+                collision = true;
+                break;
+            }
+        }
+
+        if (!collision) {
+            append_screen(new_screen_rect);
+            if (is_valid()) {
+                // We got lucky!
+                screens_guard.disarm();
+                return true;
+            }
+        }
+    }
+
+    dbgln("Failed to add display connector device {} with resolution {}x{} to screen layout", device_path, mode_setting.horizontal_active, mode_setting.vertical_active);
+    return false;
+}
+
+// FIXME: Remove this once framebuffer devices are removed.
 bool ScreenLayout::try_auto_add_framebuffer(String const& device_path)
 {
     int framebuffer_fd = open(device_path.characters(), O_RDWR | O_CLOEXEC);
diff --git a/Userland/Services/WindowServer/main.cpp b/Userland/Services/WindowServer/main.cpp
index 3e12ae7c7e..eb050c70a7 100644
--- a/Userland/Services/WindowServer/main.cpp
+++ b/Userland/Services/WindowServer/main.cpp
@@ -68,7 +68,8 @@ ErrorOr<int> serenity_main(Main::Arguments)
         WindowServer::ScreenLayout screen_layout;
         String error_msg;
 
-        auto add_unconfigured_devices = [&]() {
+        // FIXME: Remove this once framebuffer devices are removed.
+        auto add_unconfigured_framebuffer_devices = [&]() {
             // Enumerate the /dev/fbX devices and try to set up any ones we find that we haven't already used
             Core::DirIterator di("/dev", Core::DirIterator::SkipParentAndBaseDir);
             while (di.has_next()) {
@@ -76,6 +77,7 @@ ErrorOr<int> serenity_main(Main::Arguments)
                 if (!path.starts_with("fb"))
                     continue;
                 auto full_path = String::formatted("/dev/{}", path);
+                dbgln("{} :", full_path);
                 if (!Core::File::is_device(full_path))
                     continue;
                 if (fb_devices_configured.find(full_path) != fb_devices_configured.end())
@@ -85,10 +87,31 @@ ErrorOr<int> serenity_main(Main::Arguments)
             }
         };
 
+        auto add_unconfigured_display_connector_devices = [&]() {
+            // Enumerate the /dev/fbX devices and try to set up any ones we find that we haven't already used
+            Core::DirIterator di("/dev/gpu", Core::DirIterator::SkipParentAndBaseDir);
+            while (di.has_next()) {
+                auto path = di.next_path();
+                if (!path.starts_with("connector"))
+                    continue;
+                auto full_path = String::formatted("/dev/gpu/{}", path);
+                if (!Core::File::is_device(full_path))
+                    continue;
+                if (fb_devices_configured.find(full_path) != fb_devices_configured.end())
+                    continue;
+                if (!screen_layout.try_auto_add_display_connector(full_path))
+                    dbgln("Could not auto-add framebuffer device {} to screen layout", full_path);
+            }
+        };
+
         auto apply_and_generate_generic_screen_layout = [&]() {
             screen_layout = {};
             fb_devices_configured = {};
-            add_unconfigured_devices();
+
+            // FIXME: Remove this once framebuffer devices are removed.
+            add_unconfigured_framebuffer_devices();
+
+            add_unconfigured_display_connector_devices();
             if (!WindowServer::Screen::apply_layout(move(screen_layout), error_msg)) {
                 dbgln("Failed to apply generated fallback screen layout: {}", error_msg);
                 return false;
@@ -100,10 +123,13 @@ ErrorOr<int> serenity_main(Main::Arguments)
 
         if (screen_layout.load_config(*wm_config, &error_msg)) {
             for (auto& screen_info : screen_layout.screens)
-                if (screen_info.mode == WindowServer::ScreenLayout::Screen::Mode::Device)
+                if (screen_info.mode == WindowServer::ScreenLayout::Screen::Mode::Device || screen_info.mode == WindowServer::ScreenLayout::Screen::Mode::DisplayConnectorDevice)
                     fb_devices_configured.set(screen_info.device.value());
 
-            add_unconfigured_devices();
+            // FIXME: Remove this once framebuffer devices are removed.
+            add_unconfigured_framebuffer_devices();
+
+            add_unconfigured_display_connector_devices();
 
             if (!WindowServer::Screen::apply_layout(move(screen_layout), error_msg)) {
                 dbgln("Error applying screen layout: {}", error_msg);