Kernel: Add ioctl to get the EDID from a framebuffer

Kernel/API/FB.h

@@ -41,6 +41,11 @@ ALWAYS_INLINE int fb_set_resolution(int fd, FBHeadResolution* info)
     return ioctl(fd, FB_IOCTL_SET_HEAD_RESOLUTION, info);
 }
 
+ALWAYS_INLINE int fb_get_head_edid(int fd, FBHeadEDID* info)
+{
+    return ioctl(fd, FB_IOCTL_GET_HEAD_EDID, info);
+}
+
 ALWAYS_INLINE int fb_get_head_vertical_offset_buffer(int fd, FBHeadVerticalOffset* vertical_offset)
 {
     return ioctl(fd, FB_IOCTL_GET_HEAD_VERTICAL_OFFSET_BUFFER, vertical_offset);

Kernel/CMakeLists.txt

@@ -343,6 +343,12 @@ set(AK_SOURCES
     ../AK/Utf16View.cpp
 )
 
+set(EDID_SOURCES
+    ../Userland/Libraries/LibEDID/DMT.cpp
+    ../Userland/Libraries/LibEDID/EDID.cpp
+    ../Userland/Libraries/LibEDID/VIC.cpp
+)
+
 set(ELF_SOURCES
     ../Userland/Libraries/LibELF/Image.cpp
     ../Userland/Libraries/LibELF/Validation.cpp
@@ -368,6 +374,7 @@ if (NOT "${SERENITY_ARCH}" STREQUAL "aarch64")
     set(SOURCES
         ${KERNEL_SOURCES}
         ${SOURCES}
+        ${EDID_SOURCES}
         ${ELF_SOURCES}
         ${VT_SOURCES}
         ${CRYPTO_SOURCES}

Kernel/Graphics/Bochs/GraphicsAdapter.cpp

@@ -276,4 +276,15 @@ void BochsGraphicsAdapter::disable_consoles()
     m_framebuffer_device->activate_writes();
 }
 
+ErrorOr<ByteBuffer> BochsGraphicsAdapter::get_edid(size_t output_port_index) const
+{
+    if (output_port_index != 0)
+        return Error::from_errno(ENODEV);
+
+    auto bytes = ByteBuffer::copy(const_cast<u8 const*>(m_registers->edid_data), sizeof(m_registers->edid_data));
+    if (!bytes.has_value())
+        return Error::from_errno(ENOMEM);
+    return bytes.release_value();
+}
+
 }

Kernel/Graphics/Bochs/GraphicsAdapter.h

@@ -36,6 +36,8 @@ public:
 
     virtual bool vga_compatible() const override;
 
+    ErrorOr<ByteBuffer> get_edid(size_t output_port_index) const override;
+
 private:
     // ^GenericGraphicsAdapter
     virtual bool try_to_set_resolution(size_t output_port_index, size_t width, size_t height) override;

Kernel/Graphics/Definitions.h

@@ -32,54 +32,4 @@ struct Modesetting {
     Timings vertical;
 };
 
-struct [[gnu::packed]] StandardTimings {
-    u8 resolution;
-    u8 frequency;
-};
-
-struct [[gnu::packed]] DetailTimings {
-    u16 pixel_clock;
-    u8 horizontal_active;
-    u8 horizontal_blank;
-    u8 horizontal_active_blank_msb;
-    u8 vertical_active;
-    u8 vertical_blank;
-    u8 vertical_active_blank_msb;
-    u8 horizontal_sync_offset;
-    u8 horizontal_sync_pulse;
-    u8 vertical_sync;
-    u8 sync_msb;
-    u8 dimension_width;
-    u8 dimension_height;
-    u8 dimension_msb;
-    u8 horizontal_border;
-    u8 vertical_border;
-    u8 features;
-};
-
-struct [[gnu::packed]] VideoInfoBlock {
-    u64 padding;
-    u16 manufacture_id;
-    u16 product_id;
-    u32 serial_number;
-    u8 manufacture_week;
-    u8 manufacture_year;
-    u8 edid_version;
-    u8 edid_revision;
-    u8 video_input_type;
-    u8 max_horizontal_size;
-    u8 max_vertical_size;
-    u8 gama_factor;
-    u8 dpms_flags;
-    u8 chroma_info[10];
-    u8 established_timing[2];
-    u8 manufacture_reserved_timings;
-    StandardTimings timings[8];
-    DetailTimings details[4];
-    u8 unused;
-    u8 checksum;
-};
-
-static_assert(AssertSize<VideoInfoBlock, 128>());
-
 }

Kernel/Graphics/FramebufferDevice.cpp

@@ -243,4 +243,12 @@ ErrorOr<void> FramebufferDevice::flush_rectangle(size_t, FBRect const&)
     VERIFY_NOT_REACHED();
 }
 
+ErrorOr<ByteBuffer> FramebufferDevice::get_edid(size_t head) const
+{
+    auto adapter = m_graphics_adapter.strong_ref();
+    if (!adapter)
+        return Error::from_errno(EIO);
+    return adapter->get_edid(head);
+}
+
 }

Kernel/Graphics/FramebufferDevice.h

@@ -40,6 +40,8 @@ public:
     virtual ErrorOr<size_t> vertical_offset(size_t head) const override;
     virtual ErrorOr<bool> vertical_offsetted(size_t head) const override;
 
+    virtual ErrorOr<ByteBuffer> get_edid(size_t head) const override;
+
 private:
     virtual ErrorOr<void> set_head_resolution(size_t head, size_t width, size_t height, size_t pitch) override;
     virtual ErrorOr<void> set_head_buffer(size_t head, bool second_buffer) override;

Kernel/Graphics/GenericFramebufferDevice.cpp

@@ -33,7 +33,11 @@ ErrorOr<void> GenericFramebufferDevice::verify_head_index(int head_index) const
 
 ErrorOr<void> GenericFramebufferDevice::ioctl(OpenFileDescription&, unsigned request, Userspace<void*> arg)
 {
+    if (request != FB_IOCTL_GET_HEAD_EDID) {
+        // Allow anyone to query the EDID. Eventually we'll publish the current EDID on /sys
+        // so it doesn't really make sense to require the video pledge to query it.
         TRY(Process::current().require_promise(Pledge::video));
+    }
     switch (request) {
     case FB_IOCTL_GET_PROPERTIES: {
         auto user_properties = static_ptr_cast<FBProperties*>(arg);
@@ -60,6 +64,26 @@ ErrorOr<void> GenericFramebufferDevice::ioctl(OpenFileDescription&, unsigned req
         head_properties.offset = TRY(vertical_offset(head_properties.head_index));
         return copy_to_user(user_head_properties, &head_properties);
     }
+    case FB_IOCTL_GET_HEAD_EDID: {
+        auto user_head_edid = static_ptr_cast<FBHeadEDID*>(arg);
+        FBHeadEDID head_edid {};
+        TRY(copy_from_user(&head_edid, user_head_edid));
+        TRY(verify_head_index(head_edid.head_index));
+
+        auto edid_bytes = TRY(get_edid(head_edid.head_index));
+        if (head_edid.bytes != nullptr) {
+            // Only return the EDID if a buffer was provided. Either way,
+            // we'll write back the bytes_size with the actual size
+            if (head_edid.bytes_size < edid_bytes.size()) {
+                head_edid.bytes_size = edid_bytes.size();
+                TRY(copy_to_user(user_head_edid, &head_edid));
+                return Error::from_errno(EOVERFLOW);
+            }
+            TRY(copy_to_user(head_edid.bytes, (void const*)edid_bytes.data(), edid_bytes.size()));
+        }
+        head_edid.bytes_size = edid_bytes.size();
+        return copy_to_user(user_head_edid, &head_edid);
+    }
     case FB_IOCTL_SET_HEAD_RESOLUTION: {
         auto user_head_resolution = static_ptr_cast<FBHeadResolution const*>(arg);
         auto head_resolution = TRY(copy_typed_from_user(user_head_resolution));

Kernel/Graphics/GenericFramebufferDevice.h

@@ -57,6 +57,8 @@ protected:
     // FIXME: This method is too much specific to the VirtIO implementation (especially the buffer_index parameter)
     virtual ErrorOr<void> flush_rectangle(size_t buffer_index, FBRect const&) = 0;
 
+    virtual ErrorOr<ByteBuffer> get_edid(size_t head) const = 0;
+
     ErrorOr<void> verify_head_index(int head_index) const;
 
     GenericFramebufferDevice(const GenericGraphicsAdapter&);

Kernel/Graphics/GenericGraphicsAdapter.h

@@ -29,6 +29,8 @@ public:
 
     virtual bool vga_compatible() const = 0;
 
+    virtual ErrorOr<ByteBuffer> get_edid(size_t output_port_index) const = 0;
+
     virtual bool try_to_set_resolution(size_t output_port_index, size_t width, size_t height) = 0;
     virtual bool set_y_offset(size_t output_port_index, size_t y) = 0;
 

Kernel/Graphics/Intel/NativeGraphicsAdapter.cpp

@@ -62,31 +62,29 @@ static size_t compute_dac_multiplier(size_t pixel_clock_in_khz)
     }
 }
 
-static Graphics::Modesetting calculate_modesetting_from_edid(const Graphics::VideoInfoBlock& edid, size_t index)
+static Graphics::Modesetting calculate_modesetting_from_edid(EDID::Parser& edid, size_t index)
 {
-    Graphics::Modesetting mode;
-    VERIFY(edid.details[0].pixel_clock);
-    mode.pixel_clock_in_khz = edid.details[0].pixel_clock * 10;
+    auto details = edid.detailed_timing(index).release_value();
 
-    size_t horizontal_active = edid.details[index].horizontal_active | ((edid.details[index].horizontal_active_blank_msb >> 4) << 8);
-    size_t horizontal_blank = edid.details[index].horizontal_blank | ((edid.details[index].horizontal_active_blank_msb & 0xF) << 8);
-    size_t horizontal_sync_offset = edid.details[index].horizontal_sync_offset | ((edid.details[index].sync_msb >> 6) << 8);
-    size_t horizontal_sync_pulse = edid.details[index].horizontal_sync_pulse | (((edid.details[index].sync_msb >> 4) & 0x3) << 8);
+    Graphics::Modesetting mode;
+    VERIFY(details.pixel_clock_khz());
+    mode.pixel_clock_in_khz = details.pixel_clock_khz();
+
+    size_t horizontal_active = details.horizontal_addressable_pixels();
+    size_t horizontal_sync_offset = details.horizontal_front_porch_pixels();
 
     mode.horizontal.active = horizontal_active;
     mode.horizontal.sync_start = horizontal_active + horizontal_sync_offset;
-    mode.horizontal.sync_end = horizontal_active + horizontal_sync_offset + horizontal_sync_pulse;
-    mode.horizontal.total = horizontal_active + horizontal_blank;
+    mode.horizontal.sync_end = horizontal_active + horizontal_sync_offset + details.horizontal_sync_pulse_width_pixels();
+    mode.horizontal.total = horizontal_active + details.horizontal_blanking_pixels();
 
-    size_t vertical_active = edid.details[index].vertical_active | ((edid.details[index].vertical_active_blank_msb >> 4) << 8);
-    size_t vertical_blank = edid.details[index].vertical_blank | ((edid.details[index].vertical_active_blank_msb & 0xF) << 8);
-    size_t vertical_sync_offset = (edid.details[index].vertical_sync >> 4) | (((edid.details[index].sync_msb >> 2) & 0x3) << 4);
-    size_t vertical_sync_pulse = (edid.details[index].vertical_sync & 0xF) | ((edid.details[index].sync_msb & 0x3) << 4);
+    size_t vertical_active = details.vertical_addressable_lines();
+    size_t vertical_sync_offset = details.vertical_front_porch_lines();
 
     mode.vertical.active = vertical_active;
     mode.vertical.sync_start = vertical_active + vertical_sync_offset;
-    mode.vertical.sync_end = vertical_active + vertical_sync_offset + vertical_sync_pulse;
-    mode.vertical.total = vertical_active + vertical_blank;
+    mode.vertical.sync_end = vertical_active + vertical_sync_offset + details.vertical_sync_pulse_width_lines();
+    mode.vertical.total = vertical_active + details.vertical_blanking_lines();
     return mode;
 }
 
@@ -202,7 +200,7 @@ IntelNativeGraphicsAdapter::IntelNativeGraphicsAdapter(PCI::Address address)
     }
     gmbus_read_edid();
 
-    auto modesetting = calculate_modesetting_from_edid(m_crt_edid, 0);
+    auto modesetting = calculate_modesetting_from_edid(m_crt_edid.value(), 0);
     dmesgln("Intel Native Graphics Adapter @ {}, preferred resolution is {:d}x{:d}", pci_address(), modesetting.horizontal.active, modesetting.vertical.active);
     set_crt_resolution(modesetting.horizontal.active, modesetting.vertical.active);
     auto framebuffer_address = PhysicalAddress(PCI::get_BAR2(pci_address()) & 0xfffffff0);
@@ -377,9 +375,17 @@ void IntelNativeGraphicsAdapter::gmbus_read(unsigned address, u8* buf, size_t le
 
 void IntelNativeGraphicsAdapter::gmbus_read_edid()
 {
+    {
         SpinlockLocker control_lock(m_control_lock);
         gmbus_write(DDC2_I2C_ADDRESS, 0);
-    gmbus_read(DDC2_I2C_ADDRESS, (u8*)&m_crt_edid, sizeof(Graphics::VideoInfoBlock));
+        gmbus_read(DDC2_I2C_ADDRESS, (u8*)&m_crt_edid_bytes, sizeof(m_crt_edid_bytes));
+    }
+    if (auto parsed_edid = EDID::Parser::from_bytes({ m_crt_edid_bytes, sizeof(m_crt_edid_bytes) }); !parsed_edid.is_error()) {
+        m_crt_edid = parsed_edid.release_value();
+    } else {
+        dbgln("IntelNativeGraphicsAdapter: Parsing EDID failed: {}", parsed_edid.error());
+        m_crt_edid = {};
+    }
 }
 
 bool IntelNativeGraphicsAdapter::is_resolution_valid(size_t, size_t)
@@ -420,7 +426,7 @@ bool IntelNativeGraphicsAdapter::set_crt_resolution(size_t width, size_t height)
     }
 
     // FIXME: Get the requested resolution from the EDID!!
-    auto modesetting = calculate_modesetting_from_edid(m_crt_edid, 0);
+    auto modesetting = calculate_modesetting_from_edid(m_crt_edid.value(), 0);
 
     disable_output();
 
@@ -647,4 +653,22 @@ void IntelNativeGraphicsAdapter::initialize_framebuffer_devices()
     auto framebuffer_result = m_framebuffer_device->try_to_initialize();
     VERIFY(!framebuffer_result.is_error());
 }
+
+ErrorOr<ByteBuffer> IntelNativeGraphicsAdapter::get_edid(size_t output_port_index) const
+{
+    if (output_port_index != 0) {
+        dbgln("IntelNativeGraphicsAdapter: get_edid: Only one output supported");
+        return Error::from_errno(ENODEV);
+    }
+
+    if (m_crt_edid.has_value()) {
+        auto bytes = ByteBuffer::copy(m_crt_edid_bytes, sizeof(m_crt_edid_bytes));
+        if (!bytes.has_value())
+            return Error::from_errno(ENOMEM);
+        return bytes.release_value();
+    }
+
+    return ByteBuffer {};
+}
+
 }

Kernel/Graphics/Intel/NativeGraphicsAdapter.h

@@ -12,6 +12,7 @@
 #include <Kernel/Graphics/FramebufferDevice.h>
 #include <Kernel/Graphics/VGACompatibleAdapter.h>
 #include <Kernel/PhysicalAddress.h>
+#include <LibEDID/EDID.h>
 
 namespace Kernel {
 
@@ -113,6 +114,7 @@ private:
 
     // ^GenericGraphicsAdapter
     virtual void initialize_framebuffer_devices() override;
+    virtual ErrorOr<ByteBuffer> get_edid(size_t output_port_index) const override;
 
     bool pipe_a_enabled() const;
     bool pipe_b_enabled() const;
@@ -162,7 +164,8 @@ private:
     Spinlock m_modeset_lock;
     mutable Spinlock m_registers_lock;
 
-    Graphics::VideoInfoBlock m_crt_edid;
+    EDID::Parser::RawBytes m_crt_edid_bytes {};
+    Optional<EDID::Parser> m_crt_edid;
     const PhysicalAddress m_registers;
     const PhysicalAddress m_framebuffer_addr;
     OwnPtr<Memory::Region> m_registers_region;

Kernel/Graphics/VGACompatibleAdapter.cpp

@@ -80,4 +80,9 @@ bool VGACompatibleAdapter::set_y_offset(size_t, size_t)
     return false;
 }
 
+ErrorOr<ByteBuffer> VGACompatibleAdapter::get_edid(size_t) const
+{
+    return Error::from_errno(ENOTSUP);
+}
+
 }

Kernel/Graphics/VGACompatibleAdapter.h

@@ -31,6 +31,8 @@ public:
     virtual bool try_to_set_resolution(size_t output_port_index, size_t width, size_t height) override;
     virtual bool set_y_offset(size_t output_port_index, size_t y) override;
 
+    ErrorOr<ByteBuffer> get_edid(size_t output_port_index) const override;
+
 protected:
     explicit VGACompatibleAdapter(PCI::Address);
 

Kernel/Graphics/VirtIOGPU/FramebufferDevice.cpp

@@ -140,6 +140,15 @@ ErrorOr<void> FramebufferDevice::flush_rectangle(size_t buffer_index, FBRect con
     return {};
 }
 
+ErrorOr<ByteBuffer> FramebufferDevice::get_edid(size_t head) const
+{
+    // Note: This FramebufferDevice class doesn't support multihead setup.
+    // We take care to verify this at the GenericFramebufferDevice::ioctl method
+    // so if we happen to accidentally have a value different than 0, assert.
+    VERIFY(head == 0);
+    return adapter()->get_edid(m_scanout.value());
+}
+
 FramebufferDevice::FramebufferDevice(GraphicsAdapter const& adapter, ScanoutID scanout)
     : GenericFramebufferDevice(adapter)
     , m_scanout(scanout)

Kernel/Graphics/VirtIOGPU/FramebufferDevice.h

@@ -62,6 +62,8 @@ private:
     virtual ErrorOr<void> flush_head_buffer(size_t head) override;
     virtual ErrorOr<void> flush_rectangle(size_t head, FBRect const&) override;
 
+    virtual ErrorOr<ByteBuffer> get_edid(size_t head) const override;
+
     void flush_dirty_window(Protocol::Rect const&, Buffer&);
     void transfer_framebuffer_data_to_host(Protocol::Rect const&, Buffer&);
     void flush_displayed_image(Protocol::Rect const&, Buffer&);

Kernel/Graphics/VirtIOGPU/GraphicsAdapter.cpp

@@ -78,7 +78,7 @@ void GraphicsAdapter::initialize()
             if (is_feature_set(supported_features, VIRTIO_GPU_F_VIRGL))
                 dbgln_if(VIRTIO_DEBUG, "VirtIO::GraphicsAdapter: VIRGL is not yet supported!");
             if (is_feature_set(supported_features, VIRTIO_GPU_F_EDID))
-                dbgln_if(VIRTIO_DEBUG, "VirtIO::GraphicsAdapter: EDID is not yet supported!");
+                negotiated |= VIRTIO_GPU_F_EDID;
             return negotiated;
         });
         if (success) {
@@ -93,6 +93,7 @@ void GraphicsAdapter::initialize()
         MutexLocker locker(m_operation_lock);
         // Get display information using VIRTIO_GPU_CMD_GET_DISPLAY_INFO
         query_display_information();
+        query_display_edid({});
     } else {
         VERIFY_NOT_REACHED();
     }
@@ -160,10 +161,96 @@ void GraphicsAdapter::query_display_information()
         dbgln_if(VIRTIO_DEBUG, "VirtIO::GraphicsAdapter: Scanout {}: enabled: {} x: {}, y: {}, width: {}, height: {}", i, !!scanout.enabled, scanout.rect.x, scanout.rect.y, scanout.rect.width, scanout.rect.height);
         if (scanout.enabled && !m_default_scanout.has_value())
             m_default_scanout = i;
+
+        m_scanouts[i].edid = {};
     }
     VERIFY(m_default_scanout.has_value());
 }
 
+void GraphicsAdapter::query_display_edid(Optional<ScanoutID> scanout_id)
+{
+    VERIFY(m_operation_lock.is_locked());
+
+    if (!is_feature_accepted(VIRTIO_GPU_F_EDID))
+        return;
+
+    for (size_t i = 0; i < VIRTIO_GPU_MAX_SCANOUTS; ++i) {
+        if (scanout_id.has_value() && scanout_id.value() != i)
+            continue;
+
+        // scanout.display_info.enabled doesn't seem to reflect the actual state,
+        // even if we were to call query_display_information prior to calling
+        // this function. So, just ignore, we seem to get EDID information regardless.
+
+        auto query_edid_result = query_edid(i);
+        if (query_edid_result.is_error()) {
+            dbgln("VirtIO::GraphicsAdapater: Scanout {}: Failed to parse EDID: {}", i, query_edid_result.error());
+            m_scanouts[i].edid = {};
+        } else {
+            m_scanouts[i].edid = query_edid_result.release_value();
+            if (m_scanouts[i].edid.has_value()) {
+                auto& parsed_edid = m_scanouts[i].edid.value();
+                dbgln("VirtIO::GraphicsAdapater: Scanout {}: EDID {}: Manufacturer: {} Product: {} Serial #{}", i,
+                    parsed_edid.version(), parsed_edid.legacy_manufacturer_id(), parsed_edid.product_code(), parsed_edid.serial_number());
+                if (auto screen_size = parsed_edid.screen_size(); screen_size.has_value()) {
+                    auto& size = screen_size.value();
+                    dbgln("VirtIO::GraphicsAdapater: Scanout {}:           Screen size: {}cm x {}cm", i,
+                        size.horizontal_cm(), size.vertical_cm());
+                } else if (auto aspect_ratio = parsed_edid.aspect_ratio(); aspect_ratio.has_value()) {
+                    auto& ratio = aspect_ratio.value();
+                    dbgln("VirtIO::GraphicsAdapater: Scanout {}:           Aspect ratio: {} : 1", i, ratio.ratio());
+                } else {
+                    dbgln("VirtIO::GraphicsAdapater: Scanout {}:           Unknown screen size or aspect ratio", i);
+                }
+            } else {
+                dbgln("VirtIO::GraphicsAdapater: Scanout {}: No EDID", i);
+            }
+        }
+    }
+}
+
+ErrorOr<ByteBuffer> GraphicsAdapter::get_edid(size_t output_port_index) const
+{
+    if (output_port_index >= VIRTIO_GPU_MAX_SCANOUTS)
+        return Error::from_errno(ENODEV);
+    auto& edid = m_scanouts[output_port_index].edid;
+    if (edid.has_value()) {
+        auto bytes = ByteBuffer::copy(edid.value().bytes());
+        if (!bytes.has_value())
+            return Error::from_errno(ENOMEM);
+        return bytes.release_value();
+    }
+    return ByteBuffer {};
+}
+
+auto GraphicsAdapter::query_edid(u32 scanout_id) -> ErrorOr<Optional<EDID::Parser>>
+{
+    VERIFY(m_operation_lock.is_locked());
+    auto writer = create_scratchspace_writer();
+    auto& request = writer.append_structure<Protocol::GetEDID>();
+    auto& response = writer.append_structure<Protocol::GetEDIDResponse>();
+
+    populate_virtio_gpu_request_header(request.header, Protocol::CommandType::VIRTIO_GPU_CMD_GET_EDID, VIRTIO_GPU_FLAG_FENCE);
+
+    request.scanout_id = scanout_id;
+    request.padding = 0;
+
+    synchronous_virtio_gpu_command(start_of_scratch_space(), sizeof(request), sizeof(response));
+
+    if (response.header.type != static_cast<u32>(Protocol::CommandType::VIRTIO_GPU_RESP_OK_EDID))
+        return Error::from_string_literal("VirtIO::GraphicsAdapter: Failed to get EDID");
+
+    if (response.size == 0)
+        return Error::from_string_literal("VirtIO::GraphicsAdapter: Failed to get EDID, empty buffer");
+
+    auto edid_buffer = ByteBuffer::copy(response.edid, response.size);
+    if (!edid_buffer.has_value())
+        return Error::from_errno(ENOMEM);
+
+    auto edid = TRY(EDID::Parser::from_bytes(edid_buffer.release_value()));
+    return edid;
+}
+
 ResourceID GraphicsAdapter::create_2d_resource(Protocol::Rect rect)
 {
     VERIFY(m_operation_lock.is_locked());
@@ -235,6 +322,8 @@ void GraphicsAdapter::detach_backing_storage(ResourceID resource_id)
 void GraphicsAdapter::set_scanout_resource(ScanoutID scanout, ResourceID resource_id, Protocol::Rect rect)
 {
     VERIFY(m_operation_lock.is_locked());
+    {
+        // We need to scope the request/response here so that we can query display information later on
         auto writer = create_scratchspace_writer();
         auto& request = writer.append_structure<Protocol::SetScanOut>();
         auto& response = writer.append_structure<Protocol::ControlHeader>();
@@ -248,6 +337,10 @@ void GraphicsAdapter::set_scanout_resource(ScanoutID scanout, ResourceID resourc
 
         VERIFY(response.type == static_cast<u32>(Protocol::CommandType::VIRTIO_GPU_RESP_OK_NODATA));
         dbgln_if(VIRTIO_DEBUG, "VirtIO::GraphicsAdapter: Set backing scanout");
+    }
+
+    // Now that the Scanout should be enabled, update the EDID
+    query_display_edid(scanout);
 }
 
 void GraphicsAdapter::transfer_framebuffer_data_to_host(ScanoutID scanout, ResourceID resource_id, Protocol::Rect const& dirty_rect)

Kernel/Graphics/VirtIOGPU/GraphicsAdapter.h

@@ -15,6 +15,7 @@
 #include <Kernel/Graphics/VirtIOGPU/Console.h>
 #include <Kernel/Graphics/VirtIOGPU/FramebufferDevice.h>
 #include <Kernel/Graphics/VirtIOGPU/Protocol.h>
+#include <LibEDID/EDID.h>
 
 namespace Kernel::Graphics::VirtIOGPU {
 
@@ -47,6 +48,8 @@ public:
 
     virtual void initialize() override;
 
+    ErrorOr<ByteBuffer> get_edid(size_t output_port_index) const override;
+
 private:
     void flush_dirty_rectangle(ScanoutID, ResourceID, Protocol::Rect const& dirty_rect);
 
@@ -98,6 +101,7 @@ private:
         RefPtr<Graphics::VirtIOGPU::FramebufferDevice> framebuffer;
         RefPtr<Console> console;
         Protocol::DisplayInfoResponse::Display display_info {};
+        Optional<EDID::Parser> edid;
     };
 
     virtual bool handle_device_config_change() override;
@@ -117,6 +121,7 @@ private:
     void populate_virtio_gpu_request_header(Protocol::ControlHeader& header, Protocol::CommandType ctrl_type, u32 flags = 0);
 
     void query_display_information();
+    void query_display_edid(Optional<ScanoutID>);
     ResourceID create_2d_resource(Protocol::Rect rect);
     void delete_resource(ResourceID resource_id);
     void ensure_backing_storage(ResourceID resource_id, Memory::Region const& region, size_t buffer_offset, size_t buffer_length);
@@ -124,6 +129,7 @@ private:
     void set_scanout_resource(ScanoutID scanout, ResourceID resource_id, Protocol::Rect rect);
     void transfer_framebuffer_data_to_host(ScanoutID scanout, ResourceID resource_id, Protocol::Rect const& rect);
     void flush_displayed_image(ResourceID resource_id, Protocol::Rect const& dirty_rect);
+    ErrorOr<Optional<EDID::Parser>> query_edid(u32 scanout_id);
 
     bool m_created_framebuffer_devices { false };
     Optional<ScanoutID> m_default_scanout;

Kernel/Graphics/VirtIOGPU/Protocol.h

@@ -156,4 +156,19 @@ struct ResourceFlush {
     u32 padding;
 };
 
+// Specification equivalent: struct virtio_gpu_get_edid
+struct GetEDID {
+    ControlHeader header;
+    u32 scanout_id;
+    u32 padding;
+};
+
+// Specification equivalent: struct virtio_gpu_resp_edid
+struct GetEDIDResponse {
+    ControlHeader header;
+    u32 size;
+    u32 padding;
+    u8 edid[1024];
+};
+
 }

Userland/Libraries/LibC/sys/ioctl_numbers.h

@@ -43,6 +43,13 @@ struct FBHeadResolution {
     int height;
 };
 
+struct FBHeadEDID {
+    int head_index;
+
+    unsigned char* bytes;
+    unsigned bytes_size;
+};
+
 struct FBHeadVerticalOffset {
     int head_index;
     int offsetted;
@@ -85,6 +92,7 @@ enum IOCtlNumber {
     FB_IOCTL_GET_PROPERTIES,
     FB_IOCTL_GET_HEAD_PROPERTIES,
     FB_IOCTL_SET_HEAD_RESOLUTION,
+    FB_IOCTL_GET_HEAD_EDID,
     FB_IOCTL_SET_HEAD_VERTICAL_OFFSET_BUFFER,
     FB_IOCTL_GET_HEAD_VERTICAL_OFFSET_BUFFER,
     FB_IOCTL_FLUSH_HEAD_BUFFERS,
@@ -133,6 +141,7 @@ enum IOCtlNumber {
 #define TIOCSWINSZ TIOCSWINSZ
 #define FB_IOCTL_GET_PROPERTIES FB_IOCTL_GET_PROPERTIES
 #define FB_IOCTL_GET_HEAD_PROPERTIES FB_IOCTL_GET_HEAD_PROPERTIES
+#define FB_IOCTL_GET_HEAD_EDID FB_IOCTL_GET_HEAD_EDID
 #define FB_IOCTL_SET_HEAD_RESOLUTION FB_IOCTL_SET_HEAD_RESOLUTION
 #define FB_IOCTL_SET_HEAD_VERTICAL_OFFSET_BUFFER FB_IOCTL_SET_HEAD_VERTICAL_OFFSET_BUFFER
 #define FB_IOCTL_GET_HEAD_VERTICAL_OFFSET_BUFFER FB_IOCTL_GET_HEAD_VERTICAL_OFFSET_BUFFER