static struct drm_device drm;static struct drm_plane primary;static struct drm_crtc crtc;static struct drm_encoder encoder;static struct drm_connector connector;static struct hrtimer vblank_hrtimer;

static enum hrtimer_restart vkms_vblank_simulate(struct hrtimer *timer){ drm_crtc_handle_vblank(&crtc);

 hrtimer_forward_now(&vblank_hrtimer, 16666667);

 return HRTIMER_RESTART;}

static void vkms_crtc_atomic_enable(struct drm_crtc *crtc,        struct drm_crtc_state *old_state){ hrtimer_init(&vblank_hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); vblank_hrtimer.function = &vkms_vblank_simulate; hrtimer_start(&vblank_hrtimer, 16666667, HRTIMER_MODE_REL);}

static void vkms_crtc_atomic_disable(struct drm_crtc *crtc,         struct drm_crtc_state *old_state){ hrtimer_cancel(&vblank_hrtimer);}

static void vkms_crtc_atomic_flush(struct drm_crtc *crtc,       struct drm_crtc_state *old_crtc_state){ unsigned long flags;

 if (crtc->state->event) {  spin_lock_irqsave(&crtc->dev->event_lock, flags);  drm_crtc_send_vblank_event(crtc, crtc->state->event);  spin_unlock_irqrestore(&crtc->dev->event_lock, flags);

  crtc->state->event = NULL; }}

static const struct drm_crtc_helper_funcs vkms_crtc_helper_funcs = { .atomic_enable = vkms_crtc_atomic_enable, .atomic_disable = vkms_crtc_atomic_disable, .atomic_flush = vkms_crtc_atomic_flush,};

static const struct drm_crtc_funcs vkms_crtc_funcs = { .set_config             = drm_atomic_helper_set_config, .page_flip              = drm_atomic_helper_page_flip, .destroy                = drm_crtc_cleanup, .reset                  = drm_atomic_helper_crtc_reset, .atomic_duplicate_state = drm_atomic_helper_crtc_duplicate_state, .atomic_destroy_state   = drm_atomic_helper_crtc_destroy_state,};

static void vkms_plane_atomic_update(struct drm_plane *plane,          struct drm_plane_state *old_state){}

static const struct drm_plane_helper_funcs vkms_plane_helper_funcs = { .atomic_update  = vkms_plane_atomic_update,};

static const struct drm_plane_funcs vkms_plane_funcs = { .update_plane  = drm_atomic_helper_update_plane, .disable_plane  = drm_atomic_helper_disable_plane, .destroy   = drm_plane_cleanup, .reset    = drm_atomic_helper_plane_reset, .atomic_duplicate_state = drm_atomic_helper_plane_duplicate_state, .atomic_destroy_state = drm_atomic_helper_plane_destroy_state,};

static int vkms_conn_get_modes(struct drm_connector *connector){ int count;

 count = drm_add_modes_noedid(connector, 8192, 8192); drm_set_preferred_mode(connector, 1024, 768);

 return count;}

static const struct drm_connector_helper_funcs vkms_conn_helper_funcs = { .get_modes = vkms_conn_get_modes,};

static const struct drm_connector_funcs vkms_connector_funcs = { .fill_modes = drm_helper_probe_single_connector_modes, .destroy = drm_connector_cleanup, .reset = drm_atomic_helper_connector_reset, .atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state, .atomic_destroy_state = drm_atomic_helper_connector_destroy_state,};

static const struct drm_encoder_funcs vkms_encoder_funcs = { .destroy = drm_encoder_cleanup,};

static const struct drm_mode_config_funcs vkms_mode_funcs = { .fb_create = drm_fb_cma_create, .atomic_check = drm_atomic_helper_check, .atomic_commit = drm_atomic_helper_commit,};

static const u32 vkms_formats[] = { DRM_FORMAT_XRGB8888,};

static void vkms_modeset_init(void){ drm_mode_config_init(&drm); drm.mode_config.max_width = 8192; drm.mode_config.max_height = 8192; drm.mode_config.funcs = &vkms_mode_funcs;

 drm_universal_plane_init(&drm, &primary, 0, &vkms_plane_funcs,     vkms_formats, ARRAY_SIZE(vkms_formats),     NULL, DRM_PLANE_TYPE_PRIMARY, NULL); drm_plane_helper_add(&primary, &vkms_plane_helper_funcs);

 drm_crtc_init_with_planes(&drm, &crtc, &primary, NULL, &vkms_crtc_funcs, NULL); drm_crtc_helper_add(&crtc, &vkms_crtc_helper_funcs);

 drm_encoder_init(&drm, &encoder, &vkms_encoder_funcs, DRM_MODE_ENCODER_VIRTUAL, NULL);

 drm_connector_init(&drm, &connector, &vkms_connector_funcs, DRM_MODE_CONNECTOR_VIRTUAL); drm_connector_helper_add(&connector, &vkms_conn_helper_funcs); drm_mode_connector_attach_encoder(&connector, &encoder);

 drm_mode_config_reset(&drm);}

static const struct file_operations vkms_fops = { .owner = THIS_MODULE, .open = drm_open, .release = drm_release, .unlocked_ioctl = drm_ioctl, .poll = drm_poll, .read = drm_read, .mmap = drm_gem_cma_mmap,};

static struct drm_driver vkms_driver = { .driver_features = DRIVER_MODESET | DRIVER_GEM | DRIVER_ATOMIC, .fops   = &vkms_fops,

 .dumb_create = drm_gem_cma_dumb_create, .gem_vm_ops  = &drm_gem_cma_vm_ops, .gem_free_object_unlocked = drm_gem_cma_free_object,

 .name   = "vkms", .desc   = "Virtual Kernel Mode Setting", .date   = "20180514", .major   = 1, .minor   = 0,};

static int __init vkms_init(void){ drm_dev_init(&drm, &vkms_driver, NULL);

 vkms_modeset_init();

 drm_vblank_init(&drm, 1);

 drm.irq_enabled = true;

 drm_dev_register(&drm, 0);

 return 0;}

module_init(vkms_init);