youts or that do not
* work with normal memory mapped access
*/
ssize_t (*fb_read)(struct fb_info *info, char __user *buf,
size_t count, loff_t *ppos);
ssize_t (*fb_write)(struct fb_info *info, const char __user *buf,
size_t count, loff_t *ppos);
检测可变参数，并调整到支持的值
/* checks var and eventually tweaks it to something supported,
* DO NOT MODIFY PAR */
int (*fb_check_var)(struct fb_var_screeninfo *var, struct fb_info *info);
设置视频模式
/* set the video mode according to info->var */
int (*fb_set_par)(struct fb_info *info);
设置color寄存器的值
/* set color register */
int (*fb_setcolreg)(unsigned regno, unsigned red, unsigned green,
unsigned blue, unsigned transp, struct fb_info *info);
批量设置color寄存器，设置颜色表
/* set color registers in batch */
int (*fb_setcmap)(struct fb_cmap *cmap, struct fb_info *info);
显示空白
/* blank display */
int (*fb_blank)(int blank, struct fb_info *info);
pan显示
/* pan display */
int (*fb_pan_display)(struct fb_var_screeninfo *var, struct fb_info *info);
填充矩形
/* Draws a rectangle */
void (*fb_fillrect) (struct fb_info *info, const struct fb_fillrect *rect);
数据复制
/* Copy data from area to another */
void (*fb_copyarea) (struct fb_info *info, const struct fb_copyarea *region);
图形填充
/* Draws a image to the display */
void (*fb_imageblit) (struct fb_info *info, const struct fb_image *image);
绘制光标
/* Draws cursor */
int (*fb_cursor) (struct fb_info *info, struct fb_cursor *cursor);
旋转显示
/* Rotates the display */
void (*fb_rotate)(struct fb_info *info, int angle);
等待blit空闲
/* wait for blit idle, optional */
int (*fb_sync)(struct fb_info *info);
fb特定的ioctl操作
/* perform fb specific ioctl (optional) */
int (*fb_ioctl)(struct fb_info *info, unsigned int cmd,
unsigned long arg);
处理32兼容的ioctl操作
/* Handle 32bit compat ioctl (optional) */
int (*fb_compat_ioctl)(struct fb_info *info, unsigned cmd,
unsigned long arg);
fb特定的mmap操作
/* perform fb specific mmap */
int (*fb_mmap)(struct fb_info *info, struct vm_area_struct *vma);
保存目前的硬件状态
/* save current hardware state */
void (*fb_save_state)(struct fb_info *info);
恢复被保存的硬件状态
/* restore saved state */
void (*fb_restore_state)(struct fb_info *info);
通过fb_info获得framebuffer的能力
/* get capability given var */
void (*fb_get_caps)(struct fb_info *info, struct fb_blit_caps *caps,
struct fb_var_screeninfo *var);
};
（3）、
fb_fix_screeninfo结构体中，记录了用户不能修改的固定显示控制器参数。这些固定的参数如缓冲区的物理地址、缓冲区的长度等等。
struct fb_fix_screeninfo {
char id[16]; /* identification string eg "TT Builtin" */
字符串形式的标识符
unsigned long smem_start;/* Start of frame buffer mem */
/* (physical address) */
fb缓存的开始位置
__u32 smem_len;/* Length of frame buffer mem */
fb缓存的长度
__u32 type; /* see FB_TYPE_* */
FB_TYPE_*类型
__u32 type_aux;/* Interleave for interleaved Planes */
分界
__u32 visual; /* see FB_VISUAL_* */
屏幕使用的色彩模式
__u16 xpanstep;/* zero if no hardware panning */
如果没有硬件panning ，赋0
__u16 ypanstep;/* zero if no hardware panning */
__u16 ywrapstep;/* zero if no hardware ywrap */
1行的字节数
__u32 line_length;/* length of a line in bytes */
内存映射I/O的开始位置
unsigned long mmio_start;/* Start of Memory Mapped I/O */
/* (physical address) */
内存映射I/O的长度
__u32 mmio_len;/* Length of Memory Mapped I/O */
__u32 accel; /* Indicate to driver which */
/* specific chip/card we have*/
__u16 reserved[3];/* Reserved for future compatibility */
};
（4）、
fb_var_sc |