I/O Control Interfaces (Writing Device Drivers)

Writing Device Drivers

I/O Control Interfaces

During normal system activity, the kernel terminal emulator communicates with the console frame buffer driver through the ioctl interfaces listed in the following table:

`ioctl` Name	Corresponding Data Structure	Description
`VIS_DEVINIT`	`vis_devinit`	Initializes the session between the terminal emulator module and the frame buffer. See `VIS_DEVINIT`.
`VIS_DEVFINI`	Not Applicable	Terminates the session between the terminal emulator module and the frame buffer. See `VIS_DEFINI`.
`VIS_CONSDISPLAY`	`vis_consdisplay`	Displays pixels as a rectangle. See `VIS_CONSDISPLAY`.
`VIS_CONSCOPY`	`vis_conscopy`	Copies a rectangle of pixels (scroll). See `VIS_CONSCOPY`.
`VIS_CONSCURSOR`	`vis_conscursor`	Displays or hides a text cursor. See `VIS_CONSCURSOR`.
`VIS_PUTCMAP`	`vis_cmap`	Sends the terminal emulator module color map to the frame buffer driver. See `VIS_PUTCMAP`.
`VIS_GETCMAP`	`vis_cmap`	Reads the terminal emulator module color map from the frame buffer. See `VIS_GETCMAP`.