NAME
vcons —
generic virtual console
framework
SYNOPSIS
#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);
DESCRIPTION
These functions are used to setup and control the generic virtual console
framework.
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.
USAGE
To use vcons with a driver it needs to be initialized by calling
vcons_init(), usually in the driver's attach function.
-
-
- vd
- should be a pointer to the driver's struct
vcons_data.
-
-
- cookie
- should be a pointer to the driver's softc.
-
-
- desc
- should point to a struct
wsscreen_descr describing the default screen type for this
display.
-
-
- accops
- points to the driver's struct
wsdisplay_accessops so 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:
-
-
- cookie
- is the cookie passed to vcons_init()
-
-
- scr
- points to the struct vcons_screen
being added, its scr_ri member, a
struct rasops_info, needs to be filled in.
-
-
- existing
- is non-zero if the screen already exists and is only added
to the list.
-
-
- defattr
- points to the screen's default text attribute. It's filled
in by 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:
-
-
- scr_ri
- contains the struct rasops_info
describing the screen's geometry, access methods and so on.
-
-
- scr_cookie
- the value passed as cookie to
vcons_init(). Usually the driver's softc.
-
-
- scr_vd
- the driver's struct vcons_data.
-
-
- scr_flags
- can be zero or any combination of:
VCONS_NO_REDRAW
- don't call vcons_redraw_screen() when
this screen becomes visible.
VCONS_SCREEN_IS_STATIC
- don't
free(9) this screen's
struct vcons_screen in
free_screen() - useful if the screen has been
statically allocated.
-
-
- scr_status
- currently contains only one flag,
VCONS_IS_VISIBLE
, which is set when the screen is
visible.
SEE ALSO
wscons(4),
wsdisplay(4)