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Kernel: Implement buffer flipping for VirtIOGPU framebuffers

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This solves tearing issues and improves performance when updating the
VirtIOGPU framebuffers.
This commit is contained in:
Tom 2021-07-03 20:42:38 -06:00 • committed by Andreas Kling
parent 6e792553f2
commit 7fdf902e4a
7 changed files with 148 additions and 65 deletions
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40
Kernel/Graphics/VirtIOGPU/VirtIOFrameBufferDevice.h
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@ -14,6 +14,13 @@
namespace Kernel::Graphics {
class VirtIOFrameBufferDevice final : public BlockDevice {
friend class VirtIOGPUConsole;
struct Buffer {
size_t framebuffer_offset { 0 };
u8* framebuffer_data { nullptr };
VirtIOGPUResourceID resource_id { 0 };
};
public:
VirtIOFrameBufferDevice(VirtIOGPU& virtio_gpu, VirtIOGPUScanoutID);
virtual ~VirtIOFrameBufferDevice() override;
@ -22,23 +29,23 @@ public:
virtual void activate_writes();
bool try_to_set_resolution(size_t width, size_t height);
void clear_to_black();
void clear_to_black(Buffer&);
size_t width() const { return display_info().rect.width; }
size_t height() const { return display_info().rect.height; }
size_t pitch() const { return display_info().rect.width * 4; }
size_t size_in_bytes() const;
static size_t calculate_framebuffer_size(size_t width, size_t height)
{
return sizeof(u32) * width * height;
// VirtIO resources can only map on page boundaries!
return page_round_up(sizeof(u32) * width * height);
}
void flush_dirty_window(VirtIOGPURect const&);
void transfer_framebuffer_data_to_host(VirtIOGPURect const&);
void flush_displayed_image(VirtIOGPURect const&);
void flush_dirty_window(VirtIOGPURect const&, Buffer&);
void transfer_framebuffer_data_to_host(VirtIOGPURect const&, Buffer&);
void flush_displayed_image(VirtIOGPURect const&, Buffer&);
void draw_ntsc_test_pattern();
void draw_ntsc_test_pattern(Buffer&);
u8* framebuffer_data();
@ -49,6 +56,8 @@ private:
VirtIOGPURespDisplayInfo::VirtIOGPUDisplayOne& display_info();
void create_framebuffer();
void create_buffer(Buffer&, size_t, size_t);
void set_buffer(int);
virtual int ioctl(FileDescription&, unsigned request, FlatPtr arg) override;
virtual KResultOr<Region*> mmap(Process&, FileDescription&, const Range&, u64 offset, int prot, bool shared) override;
@ -61,11 +70,26 @@ private:
virtual mode_t required_mode() const override { return 0666; }
virtual String device_name() const override { return String::formatted("fb{}", minor()); }
static bool is_valid_buffer_index(int buffer_index)
{
return buffer_index == 0 || buffer_index == 1;
}
Buffer& buffer_from_index(int buffer_index)
{
return buffer_index == 0 ? m_main_buffer : m_back_buffer;
}
Buffer& current_buffer() const { return *m_current_buffer; }
VirtIOGPU& m_gpu;
const VirtIOGPUScanoutID m_scanout;
VirtIOGPUResourceID m_resource_id { 0 };
Buffer* m_current_buffer { nullptr };
Atomic<int, AK::memory_order_relaxed> m_last_set_buffer_index { 0 };
Buffer m_main_buffer;
Buffer m_back_buffer;
OwnPtr<Region> m_framebuffer;
RefPtr<VMObject> m_framebuffer_sink_vmobject;
size_t m_buffer_size { 0 };
bool m_are_writes_active { true };
// FIXME: This needs to be cleaned up if the WindowServer exits while we are in a tty
WeakPtr<Region> m_userspace_mmap_region;