Copyright (c) 2006 Michael Lorenz
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.Dd February 12, 2006 .Dt VCONS 9 .Os .Sh NAME .Nm vcons .Nd generic virtual console framework .Sh SYNOPSIS n wscons/wsdisplay_vconsvar.h .Ft int .Fn vcons_init "struct vcons_data *vd" "void *cookie" \ "struct wsscreen_descr *desc" "struct wsdisplay_accessops *accops" .Ft int .Fn vcons_init_screen "struct vcons_data *vd" "struct vcons_screen *scr" \ "int exists" "long *defattr" .Ft void .Fn vcons_redraw_screen "struct vcons_screen *scr" .Sh DESCRIPTION These functions are used to setup and control the generic virtual console framework.
p
The
.Fn vcons_init
function initializes the framework, it needs to be called for each
driver that's going to use
.Nm .
p .Fn vcons_init_screen adds a virtual screen to a display.
p .Fn vcons_redraw_screen redraws a screen. A driver should call it when returning to terminal emulation mode, for instance when X exits.
p
.Vt 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.
p
.Vt struct vcons_screen
describes a virtual screen.
.Sh USAGE
To use vcons with a driver it needs to be initialized by calling
.Fn vcons_init ,
usually in the driver's attach function.
l -tag -width cookieXX t Fa vd should be a pointer to the driver's
.Vt struct vcons_data .
t Fa cookie should be a pointer to the driver's softc.
t Fa desc should point to a
.Vt struct wsscreen_descr
describing the default screen type for this display.
t Fa accops points to the driver's
.Vt struct wsdisplay_accessops
so
.Fn vcons_init
can fill it in with its own implementations of
.Fn alloc_screen ,
.Fn free_screen ,
and
.Fn show_screen .
.El
p A driver should however provide its own .Fn ioctl and .Fn mmap implementations. Both will receive a pointer to the driver's .Vt struct vcons_data as first parameter.
p 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 .Vt struct rasops_info describing the screen. After that the drawing methods in .Vt 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 .Fn 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 .Vt struct rasops_info , and add the screen to a list kept in .Vt struct vcons_data .
p The callback needs to have this form:
p .Ft void .Fn init_screen "void *cookie" "struct vcons_screen *scr" "int existing" \ "long *defattr"
p and should be stored in the .Va init_screen member found in .Vt struct vcons_data . The arguments are: l -tag -width cookieXX t Fa cookie is the cookie passed to .Fn vcons_init t Fa scr points to the .Vt struct vcons_screen being added, its .Va scr_ri member, a .Vt struct rasops_info , needs to be filled in. t Fa existing is non-zero if the screen already exists and is only added to the list. t Fa defattr points to the screen's default text attribute. It's filled in by .Fn vcons_init_screen by calling the .Fn alloc_attr method found in .Vt struct rasops_info . .El
p When attaching a .Xr wsdisplay 9 the .Va accesscookie member of the .Vt struct wsemuldisplaydev_attach_args passed to .Fn config_found needs to be a pointer to the driver's .Vt struct vcons_data .
p The following members of .Vt struct vcons_screen may be of interest to drivers: l -tag -width scr_cookieXX t Va scr_ri contains the .Vt struct rasops_info describing the screen's geometry, access methods and so on. t Va scr_cookie the value passed as cookie to .Fn vcons_init . Usually the driver's softc. t Va scr_vd the driver's .Vt struct vcons_data . t Va scr_flags can be zero or any combination of: l -tag -width XXXXXXXXXXXXXXXXXXXXXX -compact t Dv VCONS_NO_REDRAW don't call .Fn vcons_redraw_screen when this screen becomes visible. t Dv VCONS_SCREEN_IS_STATIC don't .Xr free 9 this screen's .Vt struct vcons_screen in .Fn free_screen - useful if the screen has been statically allocated. .El t Va scr_status currently contains only one flag, .Dv VCONS_IS_VISIBLE , which is set when the screen is visible. .El .Sh SEE ALSO .Xr wscons 4 , .Xr wsdisplay 4
Indexes created Sun Sep 21 20:09:37 GMT 2025