Console Visual I/O Interfaces
The kernel terminal emulator interacts with the console frame buffer driver through two interfaces.
During normal system activity (after a successful boot of the system), communication between
the kernel terminal emulator and the console frame buffer driver is through ioctl
interfaces. During standalone mode (before system boot or during debugging), communication between the kernel
terminal emulator and the console frame buffer driver is through polled I/O interfaces.
All activity between the kernel terminal emulator and the console frame buffer driver
is initiated by the kernel terminal emulator, with the exception of a callback
function used by the console frame buffer driver to notify the kernel terminal
emulator of changes in the video mode.
The console visual I/O interfaces are documented in detail in the visual_io(7I)
man page. For more information on the video mode change callback function, see
Video Mode Change Callback Interface.
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. |
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. |
Video Mode Change Callback Interface
The console frame buffer driver and the kernel terminal emulator must be in
agreement about the video mode at all times. Video mode includes the console
screen height, width, and depth in pixels. Video mode also includes whether communication
between the kernel terminal emulator and the console frame buffer is in VGA
text mode or pixel mode.
In order for the console frame buffer driver to notify the kernel
terminal emulator of changes in the video mode, the console frame buffer driver
is initialized with the address of the (*modechg_cb)() kernel terminal emulator callback function described
in the following table:
Callback Function |
Corresponding Data Structures |
Description |
|---|
(*modechg_cb)() |
vis_modechg_arg vis_devinit |
Keep the terminal emulator module synchronized
with the driver video mode (screen height, width, and pixel depth). |
