数据结构

drm_crtc

struct drm_crtc {
    struct drm_device *dev;
    struct device_node *port;
    struct list_head head;
    char *name;
    struct drm_modeset_lock mutex;
    struct drm_mode_object base;
    struct drm_plane *primary; // for legacy IOCTL
    struct drm_plane *cursor; // for legacy IOCTL
    unsigned index;
    int cursor_x; // legacy
    int cursor_y; // legacy
    bool enabled; // legacy
    struct drm_display_mode mode;  // legacy
    struct drm_display_mode hwmode; // legacy
    int x; // legacy
    int y; // legacy
    const struct drm_crtc_funcs *funcs;
    uint32_t gamma_size; // legacy
    uint16_t *gamma_store; // legacy
    const struct drm_crtc_helper_funcs *helper_private;
    struct drm_object_properties properties;
    struct drm_property *scaling_filter_property;
    struct drm_crtc_state *state;
    struct list_head commit_list;
    spinlock_t commit_lock;
    struct dentry *debugfs_entry;
    struct drm_crtc_crc crc;
    unsigned int fence_context;
    spinlock_t fence_lock;
    unsigned long fence_seqno;
    char timeline_name[32];
    struct drm_self_refresh_data *self_refresh_data;
};

drm_crtc_state

struct drm_crtc_state {
    struct drm_crtc *crtc;
    bool enable;
    bool active;
    bool planes_changed : 1;
    bool mode_changed : 1;
    bool active_changed : 1;
    bool connectors_changed : 1;
    bool zpos_changed : 1;
    bool color_mgmt_changed : 1;
    bool no_vblank : 1;
    u32 plane_mask;
    u32 connector_mask;
    u32 encoder_mask;
    struct drm_display_mode adjusted_mode;
    struct drm_display_mode mode;
    struct drm_property_blob *mode_blob;
    struct drm_property_blob *degamma_lut;
    struct drm_property_blob *ctm;
    struct drm_property_blob *gamma_lut;
    u32 target_vblank;
    bool async_flip;
    bool vrr_enabled;
    bool self_refresh_active;
    enum drm_scaling_filter scaling_filter;
    struct drm_pending_vblank_event *event;
    struct drm_crtc_commit *commit;
    struct drm_atomic_state *state;
};

enable: crtc 是否需要 enable。

active:

drm_crtc_funcs

struct drm_crtc_funcs {
    void (*reset)(struct drm_crtc *crtc);
    int (*cursor_set)(struct drm_crtc *crtc, struct drm_file *file_priv, uint32_t handle, uint32_t width, uint32_t height);
    int (*cursor_set2)(struct drm_crtc *crtc, struct drm_file *file_priv,uint32_t handle, uint32_t width, uint32_t height, int32_t hot_x, int32_t hot_y);
    int (*cursor_move)(struct drm_crtc *crtc, int x, int y);
    int (*gamma_set)(struct drm_crtc *crtc, u16 *r, u16 *g, u16 *b,uint32_t size, struct drm_modeset_acquire_ctx *ctx);
    void (*destroy)(struct drm_crtc *crtc);
    int (*set_config)(struct drm_mode_set *set, struct drm_modeset_acquire_ctx *ctx);
    int (*page_flip)(struct drm_crtc *crtc,struct drm_framebuffer *fb,struct drm_pending_vblank_event *event,uint32_t flags, struct drm_modeset_acquire_ctx *ctx);
    int (*page_flip_target)(struct drm_crtc *crtc,struct drm_framebuffer *fb,struct drm_pending_vblank_event *event,uint32_t flags, uint32_t target, struct drm_modeset_acquire_ctx *ctx);
    int (*set_property)(struct drm_crtc *crtc, struct drm_property *property, uint64_t val);
    struct drm_crtc_state *(*atomic_duplicate_state)(struct drm_crtc *crtc);
    void (*atomic_destroy_state)(struct drm_crtc *crtc, struct drm_crtc_state *state);
    int (*atomic_set_property)(struct drm_crtc *crtc,struct drm_crtc_state *state,struct drm_property *property, uint64_t val);
    int (*atomic_get_property)(struct drm_crtc *crtc,const struct drm_crtc_state *state,struct drm_property *property, uint64_t *val);
    int (*late_register)(struct drm_crtc *crtc);
    void (*early_unregister)(struct drm_crtc *crtc);
    int (*set_crc_source)(struct drm_crtc *crtc, const char *source);
    int (*verify_crc_source)(struct drm_crtc *crtc, const char *source, size_t *values_cnt);
    const char *const *(*get_crc_sources)(struct drm_crtc *crtc, size_t *count);
    void (*atomic_print_state)(struct drm_printer *p, const struct drm_crtc_state *state);
    u32 (*get_vblank_counter)(struct drm_crtc *crtc);
    int (*enable_vblank)(struct drm_crtc *crtc);
    void (*disable_vblank)(struct drm_crtc *crtc);
    bool (*get_vblank_timestamp)(struct drm_crtc *crtc,int *max_error,ktime_t *vblank_time, bool in_vblank_irq);
};

.reset: optional hook，reset crtc。通用接口 drm_atomic_helper_crtc_reset。

cursor_set: optional hook, deprecated legacy support。
cursor_set2: optional hook, deprecated legacy support。
cursor_move: optional hook, deprecated legacy support。

gamma_set: optional hook,

.enable_vblank: 在这里 enable vblank interrupt。

.disable_vblank: disable vblank interrupt。

get_vblank_counter: optional hook, 获取当前硬件的 vblank 数量，如果为 NULL, kernel 会根据 timestamp 计算在中断中错过的 vblank 事件。

drm_crtc_helper_funcs

struct drm_crtc_helper_funcs {
	void (*dpms)(struct drm_crtc *crtc, int mode);
	void (*prepare)(struct drm_crtc *crtc);
	void (*commit)(struct drm_crtc *crtc);
	enum drm_mode_status (*mode_valid)(struct drm_crtc *crtc,
					   const struct drm_display_mode *mode);
	bool (*mode_fixup)(struct drm_crtc *crtc,
			   const struct drm_display_mode *mode,
			   struct drm_display_mode *adjusted_mode);

	int (*mode_set)(struct drm_crtc *crtc, struct drm_display_mode *mode,
			struct drm_display_mode *adjusted_mode, int x, int y,
			struct drm_framebuffer *old_fb);
	void (*mode_set_nofb)(struct drm_crtc *crtc);
	int (*mode_set_base)(struct drm_crtc *crtc, int x, int y,
			     struct drm_framebuffer *old_fb);

	int (*mode_set_base_atomic)(struct drm_crtc *crtc,
				    struct drm_framebuffer *fb, int x, int y,
				    enum mode_set_atomic);
	void (*disable)(struct drm_crtc *crtc);
	int (*atomic_check)(struct drm_crtc *crtc,
			    struct drm_atomic_state *state);
	void (*atomic_begin)(struct drm_crtc *crtc,
			     struct drm_atomic_state *state);
	void (*atomic_flush)(struct drm_crtc *crtc,
			     struct drm_atomic_state *state);
	void (*atomic_enable)(struct drm_crtc *crtc,
			      struct drm_atomic_state *state);
	void (*atomic_disable)(struct drm_crtc *crtc,
			       struct drm_atomic_state *state);
	bool (*get_scanout_position)(struct drm_crtc *crtc,
				     bool in_vblank_irq, int *vpos, int *hpos,
				     ktime_t *stime, ktime_t *etime,
				     const struct drm_display_mode *mode);
};

atomic_check: optional hook, 在 plane update 时检查 CRTC 的限制。在函数 drm_atomic_helper_check_planes 中被调用。

atomic_flush: optional hook,

atomic_enable: optional hook, enable crtc。

函数

初始化 crtc 函数:

drmm_crtc_alloc_with_planes(dev, type, member, primary, cursor, funcs, name, ...);
void *__drmm_crtc_alloc_with_planes(struct drm_device *dev,
				    size_t size, size_t offset,
				    struct drm_plane *primary,
				    struct drm_plane *cursor,
				    const struct drm_crtc_funcs *funcs,
				    const char *name, ...)
int drmm_crtc_init_with_planes(struct drm_device *dev, struct drm_crtc *crtc,
			       struct drm_plane *primary,
			       struct drm_plane *cursor,
			       const struct drm_crtc_funcs *funcs,
			       const char *name, ...)