test

Writing Device Drivers

Polled I/O Interfaces

The polled I/O interfaces provide the same functionality as the VIS_CONSDISPLAY, VIS_CONSCOPY, and VIS_CONSCURSOR ioctl interfaces. The polled I/O interfaces are called only when the operating system is quiesced and in standalone mode. See Implementing Polled I/O in Console Frame Buffer Drivers for more information.

While in standalone mode, the kernel terminal emulator communicates with the console frame buffer driver through the polled I/O interfaces listed in the following table:

Polled I/O Function 

Corresponding Data Structure 

Description 

(*display)()

vis_consdisplay

Displays pixels as a rectangle. 

(*copy)()

vis_conscopy

Copies a rectangle of pixels (scroll). 

(*cursor)()

vis_conscursor

Displays or hides a text cursor.