vulkan-wsi-layer/wsi/display/drm_display.hpp

/*
 * Copyright (c) 2024-2025 Arm Limited.
 *
 * SPDX-License-Identifier: MIT
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to
 * deal in the Software without restriction, including without limitation the
 * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
 * sell copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

#pragma once

#include <vulkan/vulkan.h>
#include <xf86drmMode.h>
#include <xf86drm.h>
#include <optional>

#include "util/custom_allocator.hpp"
#include "util/file_descriptor.hpp"
#include "wsi/surface.hpp"

namespace wsi
{

namespace display
{

/* Owner types for DRM API objects */
template <typename T, void (*drm_object_free)(T *)>
struct drm_deleter
{
   void operator()(T *object)
   {
      if (object != nullptr)
      {
         drm_object_free(object);
      }
   }
};

template <typename T, void (*drm_object_free)(T *)>
using drm_owner = std::unique_ptr<T, drm_deleter<T, drm_object_free>>;
using drm_resources_owner = drm_owner<_drmModeRes, drmModeFreeResources>;
using drm_connector_owner = drm_owner<_drmModeConnector, drmModeFreeConnector>;
using drm_encoder_owner = drm_owner<_drmModeEncoder, drmModeFreeEncoder>;
using drm_plane_owner = drm_owner<_drmModePlane, drmModeFreePlane>;
using drm_plane_resources_owner = drm_owner<_drmModePlaneRes, drmModeFreePlaneResources>;
using drm_object_properties_owner = drm_owner<_drmModeObjectProperties, drmModeFreeObjectProperties>;
using drm_property_owner = drm_owner<_drmModeProperty, drmModeFreeProperty>;
using drm_property_blob_owner = drm_owner<_drmModePropertyBlob, drmModeFreePropertyBlob>;

/**
 * @brief Owner class for an array of DRM GEM buffer handles.
 */
template <size_t array_size>
class drm_gem_handle_array : private util::noncopyable
{
public:
   drm_gem_handle_array(int fd)
      : m_fd(fd)
   {
   }

   uint32_t &operator[](size_t size)
   {
      return m_handle[size];
   }

   uint32_t *data()
   {
      return m_handle.data();
   }

   ~drm_gem_handle_array()
   {
      for (auto handle : m_handle)
      {
         if (handle != UINT32_MAX && m_fd != -1)
         {
            drmCloseBufferHandle(m_fd, handle);
         }
      }
   }

private:
   int m_fd{ -1 };
   std::array<uint32_t, array_size> m_handle{ UINT32_MAX };
};

/* Forward declaration */
class drm_display;

/**
 * @brief The display mode object.
 * The drm_display_mode class stores information
 * about a drm mode.
 */
class drm_display_mode
{
public:
   /**
    * @brief drm_display_mode default constructor.
    */
   drm_display_mode();

   /**
    * @brief Get the width of the display mode.
    *
    * @return Width of the display mode.
    */
   uint16_t get_width() const;

   /**
    * @brief Get the height of the display mode.
    *
    * @return Height of the display mode.
    */
   uint16_t get_height() const;

   /**
    * @brief Get the display mode refresh rate.
    *
    * @return Refresh rate of the display mode.
    */
   uint32_t get_refresh_rate() const;

   /**
    * @brief Get function for the drm mode.
    */
   drmModeModeInfo get_drm_mode() const;

   /**
    * @brief Sets the drm mode info.
    *
    * @param mode The drm mode.
    */
   void set_drm_mode(drmModeModeInfo mode);

   /**
    * @brief Check if this mode is the preferred mode for the connector.
    *
    * @return true if the mode is the preferred mode, otherwise false.
    */
   bool is_preferred() const;

   /**
    * @brief Set the preferred state.
    *
    * @param preferred The state to set.
    */
   void set_preferred(bool preferred);

private:
   /**
    * @brief Cached native drm mode.
    */
   drmModeModeInfo m_drm_mode_info;

   /**
    * @brief Flag for the preferred display mode.
    */
   bool m_preferred = false;
};

/**
 * @brief The vulkan's display object.
 * The display class wraps a VkDisplayKHR.
 */
class drm_display
{
public:
   /**
    * @brief Construct and initialize a display object.
    *
    * @param allocator The allocator object that the display will use.
    * @return std::optional<drm_display> containing a display if initialization went well, otherwise std::nullopt.
    */
   static std::optional<drm_display> make_display(const util::allocator &allocator, const char *drm_device);

   static std::optional<drm_display> &get_display();

   drm_display(drm_display &&other) = default;

   drm_display &operator=(drm_display &&other) = default;

   /**
    * @brief display destructor.
    */
   ~drm_display();

   /**
    * @brief Get the display modes begin pointer.
    *
    * @return drm_display_mode* pointer to the first display mode.
    */
   drm_display_mode *get_display_modes_begin() const;

   /**
    * @brief Get the display modes end pointer.
    *
    * @return drm_display_mode* pointer past the last display mode.
    */
   drm_display_mode *get_display_modes_end() const;

   /**
    * @brief Get number of display modes.
    *
    * @return const size_t number of display modes.
    */
   size_t get_num_display_modes() const;

   /**
    * @brief Get function for drm device file descriptor.
    *
    * @return The display device file descriptor.
    */
   int get_drm_fd() const;

   /**
    * @brief Get function for the connector id.
    *
    * @return The connector id.
    */
   uint32_t get_connector_id() const;

   /**
    * @brief Get connector corresponding to the current connector id.
    *
    * @return The connector.
    */
   drmModeConnector *get_connector() const;

   /**
    * @brief Get drm resources.
    *
    * @return The drm resources pointer.
    */
   drmModeResPtr get_drm_resources() const;

   /**
    * @brief Get the supported formats for the display.
    *
    * @return Pointer to vector of supported formats.
    */
   const util::vector<util::drm::drm_format_pair> *get_supported_formats() const;

   /**
    * @brief Query the display for support for adding framebuffers with format modifiers.
    *
    * @return true if supported, otherwise false.
    */
   bool supports_fb_modifiers() const;

   /**
    * @brief Query the display for support of a specific format and modifier combination.
    *
    * @param format The format to query support for.
    * @return true if the format is supported by the display, otherwise false.
    */
   bool is_format_supported(const util::drm::drm_format_pair &format) const;

   /**
    * @brief Returns a CRTC compatible with this display's connector.
    *
    * @return The CRTC id.
    */
   int get_crtc_id() const;

   /**
    * @brief Get the max width of the display in pixels.
    */
   uint32_t get_max_width() const;

   /**
    * @brief Get the max height of the display in pixels.
    */
   uint32_t get_max_height() const;

private:
   /**
    * @brief display constructor.
    *
    * @param allocator The allocator that the display will use.
    */
   drm_display(util::fd_owner drm_fd, int crtc_id, drm_connector_owner drm_connector,
               util::unique_ptr<util::vector<util::drm::drm_format_pair>> supported_formats,
               util::unique_ptr<drm_display_mode> display_modes, size_t num_display_modes, uint32_t max_width,
               uint32_t max_height, bool supports_fb_modifiers);

   /**
    * @brief File descriptor for the display device.
    */
   util::fd_owner m_drm_fd;

   /**
    * @brief Id of CRTC compatible with the chosen connector.
    */
   int m_crtc_id;

   /**
    * @brief Handle to the drm connector.
    */
   drm_connector_owner m_drm_connector;

   /**
    * @brief Vector of supported formats for use with the display.
    */
   util::unique_ptr<util::vector<util::drm::drm_format_pair>> m_supported_formats;

   /**
    * @brief Pointer to available display modes for the connected display.
    */
   util::unique_ptr<drm_display_mode> m_display_modes;

   /**
    * @brief Number of available display modes in @ref m_display_modes.
    */
   size_t m_num_display_modes;

   /**
    * @brief Maximum display resolution width.
    */
   uint32_t m_max_width;

   /**
    * @brief Maximum display resolution height.
    */
   uint32_t m_max_height;

   /**
    * @brief Flag to indicate if the display supports framebuffers with format modifiers.
    */
   bool m_supports_fb_modifiers;
};

} /* namespace display */

} /* namespace wsi */