mirror of
https://github.com/RGBCube/serenity
synced 2025-07-25 19:37:35 +00:00
Kernel: Implement buffer flipping for VirtIOGPU framebuffers
This solves tearing issues and improves performance when updating the VirtIOGPU framebuffers.
This commit is contained in:
parent
6e792553f2
commit
7fdf902e4a
7 changed files with 148 additions and 65 deletions
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@ -15,10 +15,8 @@ VirtIOFrameBufferDevice::VirtIOFrameBufferDevice(VirtIOGPU& virtio_gpu, VirtIOGP
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, m_gpu(virtio_gpu)
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, m_scanout(scanout)
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{
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if (display_info().enabled) {
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Locker locker(m_gpu.operation_lock());
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if (display_info().enabled)
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create_framebuffer();
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}
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}
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VirtIOFrameBufferDevice::~VirtIOFrameBufferDevice()
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@ -27,39 +25,53 @@ VirtIOFrameBufferDevice::~VirtIOFrameBufferDevice()
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void VirtIOFrameBufferDevice::create_framebuffer()
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{
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auto& info = display_info();
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size_t buffer_length = page_round_up(calculate_framebuffer_size(info.rect.width, info.rect.height));
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// First delete any existing framebuffers to free the memory first
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m_framebuffer = nullptr;
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m_framebuffer_sink_vmobject = nullptr;
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// 1. Allocate frame buffer
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m_framebuffer = MM.allocate_kernel_region(buffer_length, String::formatted("VirtGPU FrameBuffer #{}", m_scanout.value()), Region::Access::Read | Region::Access::Write, AllocationStrategy::AllocateNow);
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// Allocate frame buffer for both front and back
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auto& info = display_info();
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m_buffer_size = calculate_framebuffer_size(info.rect.width, info.rect.height);
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m_framebuffer = MM.allocate_kernel_region(m_buffer_size * 2, String::formatted("VirtGPU FrameBuffer #{}", m_scanout.value()), Region::Access::Read | Region::Access::Write, AllocationStrategy::AllocateNow);
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auto write_sink_page = MM.allocate_user_physical_page(MemoryManager::ShouldZeroFill::No).release_nonnull();
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auto num_needed_pages = m_framebuffer->vmobject().page_count();
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NonnullRefPtrVector<PhysicalPage> pages;
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for (auto i = 0u; i < num_needed_pages; ++i) {
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pages.append(write_sink_page);
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}
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m_framebuffer_sink_vmobject = AnonymousVMObject::create_with_physical_pages(move(pages));
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// 2. Create BUFFER using VIRTIO_GPU_CMD_RESOURCE_CREATE_2D
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if (m_resource_id.value() != 0)
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m_gpu.delete_resource(m_resource_id);
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m_resource_id = m_gpu.create_2d_resource(info.rect);
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Locker locker(m_gpu.operation_lock());
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m_current_buffer = &buffer_from_index(m_last_set_buffer_index.load());
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create_buffer(m_main_buffer, 0, m_buffer_size);
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create_buffer(m_back_buffer, m_buffer_size, m_buffer_size);
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}
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// 3. Attach backing storage using VIRTIO_GPU_CMD_RESOURCE_ATTACH_BACKING
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m_gpu.ensure_backing_storage(*m_framebuffer, buffer_length, m_resource_id);
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// 4. Use VIRTIO_GPU_CMD_SET_SCANOUT to link the framebuffer to a display scanout.
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m_gpu.set_scanout_resource(m_scanout.value(), m_resource_id, info.rect);
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// 5. Render our test pattern
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draw_ntsc_test_pattern();
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// 6. Use VIRTIO_GPU_CMD_TRANSFER_TO_HOST_2D to update the host resource from guest memory.
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transfer_framebuffer_data_to_host(info.rect);
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// 7. Use VIRTIO_GPU_CMD_RESOURCE_FLUSH to flush the updated resource to the display.
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flush_displayed_image(info.rect);
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void VirtIOFrameBufferDevice::create_buffer(Buffer& buffer, size_t framebuffer_offset, size_t framebuffer_size)
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{
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buffer.framebuffer_offset = framebuffer_offset;
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buffer.framebuffer_data = m_framebuffer->vaddr().as_ptr() + framebuffer_offset;
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auto& info = display_info();
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// 1. Create BUFFER using VIRTIO_GPU_CMD_RESOURCE_CREATE_2D
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if (buffer.resource_id.value() != 0)
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m_gpu.delete_resource(buffer.resource_id);
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buffer.resource_id = m_gpu.create_2d_resource(info.rect);
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// 2. Attach backing storage using VIRTIO_GPU_CMD_RESOURCE_ATTACH_BACKING
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m_gpu.ensure_backing_storage(*m_framebuffer, buffer.framebuffer_offset, framebuffer_size, buffer.resource_id);
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// 3. Use VIRTIO_GPU_CMD_SET_SCANOUT to link the framebuffer to a display scanout.
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if (&buffer == m_current_buffer)
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m_gpu.set_scanout_resource(m_scanout.value(), buffer.resource_id, info.rect);
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// 4. Render our test pattern
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draw_ntsc_test_pattern(buffer);
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// 5. Use VIRTIO_GPU_CMD_TRANSFER_TO_HOST_2D to update the host resource from guest memory.
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transfer_framebuffer_data_to_host(info.rect, buffer);
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// 6. Use VIRTIO_GPU_CMD_RESOURCE_FLUSH to flush the updated resource to the display.
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if (&buffer == m_current_buffer)
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flush_displayed_image(info.rect, buffer);
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info.enabled = 1;
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}
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@ -74,25 +86,19 @@ VirtIOGPURespDisplayInfo::VirtIOGPUDisplayOne& VirtIOFrameBufferDevice::display_
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return m_gpu.display_info(m_scanout);
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}
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size_t VirtIOFrameBufferDevice::size_in_bytes() const
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void VirtIOFrameBufferDevice::transfer_framebuffer_data_to_host(VirtIOGPURect const& rect, Buffer& buffer)
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{
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auto& info = display_info();
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return info.rect.width * info.rect.height * sizeof(u32);
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m_gpu.transfer_framebuffer_data_to_host(m_scanout, rect, buffer.resource_id);
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}
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void VirtIOFrameBufferDevice::flush_dirty_window(VirtIOGPURect const& dirty_rect)
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void VirtIOFrameBufferDevice::flush_dirty_window(VirtIOGPURect const& dirty_rect, Buffer& buffer)
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{
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m_gpu.flush_dirty_window(m_scanout, dirty_rect, m_resource_id);
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m_gpu.flush_dirty_window(m_scanout, dirty_rect, buffer.resource_id);
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}
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void VirtIOFrameBufferDevice::transfer_framebuffer_data_to_host(VirtIOGPURect const& rect)
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void VirtIOFrameBufferDevice::flush_displayed_image(VirtIOGPURect const& dirty_rect, Buffer& buffer)
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{
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m_gpu.transfer_framebuffer_data_to_host(m_scanout, rect, m_resource_id);
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}
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void VirtIOFrameBufferDevice::flush_displayed_image(VirtIOGPURect const& dirty_rect)
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{
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m_gpu.flush_displayed_image(dirty_rect, m_resource_id);
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m_gpu.flush_displayed_image(dirty_rect, buffer.resource_id);
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}
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bool VirtIOFrameBufferDevice::try_to_set_resolution(size_t width, size_t height)
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@ -114,13 +120,23 @@ bool VirtIOFrameBufferDevice::try_to_set_resolution(size_t width, size_t height)
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return true;
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}
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void VirtIOFrameBufferDevice::set_buffer(int buffer_index)
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{
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auto& buffer = buffer_index == 0 ? m_main_buffer : m_back_buffer;
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Locker locker(m_gpu.operation_lock());
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if (&buffer == m_current_buffer)
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return;
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m_current_buffer = &buffer;
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m_gpu.set_scanout_resource(m_scanout.value(), buffer.resource_id, display_info().rect);
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}
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int VirtIOFrameBufferDevice::ioctl(FileDescription&, unsigned request, FlatPtr arg)
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{
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REQUIRE_PROMISE(video);
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switch (request) {
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case FB_IOCTL_GET_SIZE_IN_BYTES: {
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auto* out = (size_t*)arg;
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size_t value = size_in_bytes();
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size_t value = m_buffer_size * 2;
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if (!copy_to_user(out, &value))
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return -EFAULT;
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return 0;
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@ -147,30 +163,55 @@ int VirtIOFrameBufferDevice::ioctl(FileDescription&, unsigned request, FlatPtr a
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return -EFAULT;
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return 0;
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}
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case FB_IOCTL_SET_BUFFER: {
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auto buffer_index = (int)arg;
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if (!is_valid_buffer_index(buffer_index))
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return -EINVAL;
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if (m_last_set_buffer_index.exchange(buffer_index) != buffer_index && m_are_writes_active)
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set_buffer(buffer_index);
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return 0;
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}
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case FB_IOCTL_FLUSH_BUFFERS: {
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FBFlushRects user_flush_rects;
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if (!copy_from_user(&user_flush_rects, (FBFlushRects*)arg))
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return -EFAULT;
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if (user_flush_rects.buffer_index != 0)
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if (!is_valid_buffer_index(user_flush_rects.buffer_index))
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return -EINVAL;
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if (Checked<unsigned>::multiplication_would_overflow(user_flush_rects.count, sizeof(FBRect)))
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return -EFAULT;
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for (unsigned i = 0; i < user_flush_rects.count; i++) {
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FBRect user_dirty_rect;
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if (!copy_from_user(&user_dirty_rect, &user_flush_rects.rects[i]))
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return -EFAULT;
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if (m_are_writes_active) {
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if (m_are_writes_active && user_flush_rects.count > 0) {
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auto& buffer = buffer_from_index(user_flush_rects.buffer_index);
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Locker locker(m_gpu.operation_lock());
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for (unsigned i = 0; i < user_flush_rects.count; i++) {
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FBRect user_dirty_rect;
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if (!copy_from_user(&user_dirty_rect, &user_flush_rects.rects[i]))
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return -EFAULT;
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VirtIOGPURect dirty_rect {
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.x = user_dirty_rect.x,
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.y = user_dirty_rect.y,
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.width = user_dirty_rect.width,
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.height = user_dirty_rect.height
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};
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flush_dirty_window(dirty_rect);
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transfer_framebuffer_data_to_host(dirty_rect, buffer);
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if (&buffer == m_current_buffer) {
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// Flushing directly to screen
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flush_displayed_image(dirty_rect, buffer);
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}
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}
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}
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return 0;
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}
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case FB_IOCTL_GET_BUFFER_OFFSET: {
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FBBufferOffset buffer_offset;
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if (!copy_from_user(&buffer_offset, (FBBufferOffset*)arg))
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return -EFAULT;
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if (!is_valid_buffer_index(buffer_offset.buffer_index))
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return -EINVAL;
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buffer_offset.offset = (size_t)buffer_offset.buffer_index * m_buffer_size;
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if (!copy_to_user((FBBufferOffset*)arg, &buffer_offset))
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return -EFAULT;
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return 0;
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}
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default:
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return -EINVAL;
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};
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@ -181,9 +222,9 @@ KResultOr<Region*> VirtIOFrameBufferDevice::mmap(Process& process, FileDescripti
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REQUIRE_PROMISE(video);
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if (!shared)
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return ENODEV;
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if (offset != 0)
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if (offset != 0 || !m_framebuffer)
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return ENXIO;
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if (range.size() != page_round_up(size_in_bytes()))
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if (range.size() > m_framebuffer->size())
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return EOVERFLOW;
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// We only allow one process to map the region
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@ -217,24 +258,28 @@ void VirtIOFrameBufferDevice::deactivate_writes()
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region->set_vmobject(vm_object.release_nonnull());
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region->remap();
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}
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set_buffer(0);
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clear_to_black(buffer_from_index(0));
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}
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void VirtIOFrameBufferDevice::activate_writes()
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{
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m_are_writes_active = true;
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auto last_set_buffer_index = m_last_set_buffer_index.load();
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if (m_userspace_mmap_region) {
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auto* region = m_userspace_mmap_region.unsafe_ptr();
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region->set_vmobject(m_framebuffer->vmobject());
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region->remap();
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}
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set_buffer(last_set_buffer_index);
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}
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void VirtIOFrameBufferDevice::clear_to_black()
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void VirtIOFrameBufferDevice::clear_to_black(Buffer& buffer)
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{
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auto& info = display_info();
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size_t width = info.rect.width;
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size_t height = info.rect.height;
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u8* data = m_framebuffer->vaddr().as_ptr();
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u8* data = buffer.framebuffer_data;
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for (size_t i = 0; i < width * height; ++i) {
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data[4 * i + 0] = 0x00;
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data[4 * i + 1] = 0x00;
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@ -243,7 +288,7 @@ void VirtIOFrameBufferDevice::clear_to_black()
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}
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}
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void VirtIOFrameBufferDevice::draw_ntsc_test_pattern()
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void VirtIOFrameBufferDevice::draw_ntsc_test_pattern(Buffer& buffer)
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{
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static constexpr u8 colors[12][4] = {
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{ 0xff, 0xff, 0xff, 0xff }, // White
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@ -262,7 +307,7 @@ void VirtIOFrameBufferDevice::draw_ntsc_test_pattern()
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auto& info = display_info();
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size_t width = info.rect.width;
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size_t height = info.rect.height;
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u8* data = m_framebuffer->vaddr().as_ptr();
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u8* data = buffer.framebuffer_data;
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// Draw NTSC test card
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for (size_t y = 0; y < height; ++y) {
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for (size_t x = 0; x < width; ++x) {
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@ -302,7 +347,7 @@ void VirtIOFrameBufferDevice::draw_ntsc_test_pattern()
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u8* VirtIOFrameBufferDevice::framebuffer_data()
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{
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return m_framebuffer->vaddr().as_ptr();
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return m_current_buffer->framebuffer_data;
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}
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}
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