VCONS(9) | Kernel Developer's Manual | VCONS(9) |
vcons
—
#include
<wscons/wsdisplay_vconsvar.h>
int
vcons_init
(struct
vcons_data *vd, void
*cookie, struct
wsscreen_descr *desc,
struct wsdisplay_accessops
*accops);
int
vcons_init_screen
(struct
vcons_data *vd, struct
vcons_screen *scr, int
exists, long
*defattr);
void
vcons_redraw_screen
(struct
vcons_screen *scr);
The vcons_init
() function initializes the
framework, it needs to be called for each driver that's going to use
vcons
.
vcons_init_screen
() adds a virtual screen
to a display.
vcons_redraw_screen
() redraws a screen. A
driver should call it when returning to terminal emulation mode, for
instance when X exits.
struct vcons_data contains all information needed to manage virtual consoles on a display, usually it will be a member of the driver's softc.
struct vcons_screen describes a virtual screen.
vcons_init
(), usually in the driver's attach function.
vcons_init
() can fill it in with its own
implementations of alloc_screen
(),
free_screen
(), and
show_screen
().A driver should however provide its own
ioctl
() and mmap
()
implementations. Both will receive a pointer to the driver's
struct vcons_data as first parameter.
After initialization the driver needs to provide a callback
function that will be called whenever a screen is added. Its purpose is to
set up the struct rasops_info describing the screen.
After that the drawing methods in struct rasops_info
will be replaced with wrappers which call the original drawing functions
(which may or may not be provided by the driver) only when the respective
screen is visible. To add a virtual screen the driver one should call
vcons_init_screen
() which will call the callback
function described above, allocate storage for characters and attributes
based on whatever the callback set up in struct
rasops_info, and add the screen to a list kept in
struct vcons_data.
The callback needs to have this form:
void
init_screen
(void *cookie,
struct vcons_screen *scr, int
existing, long *defattr)
and should be stored in the init_screen member found in struct vcons_data. The arguments are:
vcons_init
()vcons_init_screen
() by calling the
alloc_attr
() method found in
struct rasops_info.When attaching a
wsdisplay(9) the
accesscookie member of the struct
wsemuldisplaydev_attach_args passed to
config_found
() needs to be a pointer to the driver's
struct vcons_data.
The following members of struct vcons_screen may be of interest to drivers:
vcons_init
().
Usually the driver's softc.VCONS_NO_REDRAW
vcons_redraw_screen
() when this
screen becomes visible.VCONS_SCREEN_IS_STATIC
free_screen
() - useful if the screen has been
statically allocated.VCONS_IS_VISIBLE
, which is set when the screen is
visible.February 12, 2006 | NetBSD 9.0 |