.\" $NetBSD: wsdisplay.4,v 1.16 2002/09/18 11:56:29 uebayasi Exp $
.Dd June 22, 2002
.Os
.Dt WSDISPLAY 4
.Sh NAME
.Nm wsdisplay
.Nd generic display device support in wscons
.Sh SYNOPSIS
.Cd wsdisplay* at ega? console ?
(EGA display on ISA)
.Cd wsdisplay* at vga? console ?
(VGA display on ISA or PCI)
.Cd wsdisplay* at pcdisplay? console ?
(generic PC (ISA) display)
.Cd wsdisplay* at tga? console ?
(DEC TGA display, alpha only)
.Cd wsdisplay* at pfb? console ?
(PCI framebuffer, bebox only)
.Cd wsdisplay0 at ofb? console ?
(Open Firmware framebuffer, macppc only)
.Cd wsdisplay* at nextdisplay? console ?
(NeXT display)
.Cd wsdisplay0 at smg0
(VAXstation small monochrome display)
.Cd wsdisplay* at ... kbdmux N
.Cd options WSDISPLAY_DEFAULTSCREENS=N
.Cd options WSDISPLAY_CHARFUNCS
.Sh DESCRIPTION
The
.Nm
driver is an abstraction layer for display devices within the
.Xr wscons 4
framework. It attaches to the hardware specific display device
driver and and makes it available as text terminal or graphics
interface.
.Pp
A display device can have the ability to display characters on it
(without help of an X server), either directly by hardware or through
software putting pixel data into the display memory.
Such displays are called
.Dq emulating ,
the
.Nm
driver will connect a terminal emulation module and provide a
tty-like software interface. In contrary, non-emulating displays can only
be used by special programs like X servers.
.Pp
The
.Em console
locator in the configuration line refers to the device's use as output
part of the operating system console. A device specification containing
a positive value here will only match if the device is in use as system
console. (The console device selection in early system startup is not
influenced.) This way, the console device can be connected to a known
wsdisplay device instance. (Naturally, only
.Dq emulating
display devices are usable as console.)
.Pp
The
.Em kbdmux
locator in the configuration line refers to the
.Xr wsmux 4
that will be used to get keyboard events.  If this locator is -1 no
mux will be used.
.Pp
The logical unit of an independent contents displayed on a display
(sometimes referred to as
.Dq virtual terminal
) is called a
.Dq screen
here. If the underlying device driver supports it, multiple screens can
be used on one display. (As of this writing, only the
.Xr vga 4
and the
.Tn VAX
.Dq smg
display drivers provide this ability.)
Screens have different minor device numbers and separate tty instances.
One screen possesses the
.Dq focus ,
this means it is visible and its tty device will get
the keyboard input. (In some cases \- if no screen is set up or if a screen
was just deleted \- it is possible that no focus is present at all.)
The focus can be switched by either special keyboard input (typically
.Tn CTRL-ALT-F Ns Ar n )
or an ioctl command issued by a user program.
Screens are created and deleted through the
.Pa /dev/ttyEcfg
control device (preferably using the
.Xr wsconscfg 8
utility). Alternatively, the compile-time option
.Dv WSDISPLAY_DEFAULTSCREENS Ns = Ns Ar n
will also create (at autoconfiguration time)
.Ar n
initial screens of the display driver's default type with
the system's default terminal emulator.
.Sh IOCTLS
The following
.Xr ioctl 2
calls are provided by the
.Nm
driver or by devices which use it.  Their definitions are found in
.Aq Pa dev/wscons/wsconsio.h .
.Bl -tag -width Dv
.It Dv WSDISPLAYIO_GTYPE Pq Li int
Retrieve the type of the display.  The list of types is in
.Aq Pa dev/wscons/wsconsio.h .
.It Dv WSDISPLAYIO_GINFO Pq Li "struct wsdisplay_fbinfo"
Retrieve basic information about a framebuffer display.
The returned structure is as follows:
.Bd -literal -offset indent
struct wsdisplay_fbinfo {
	u_int	height;
	u_int	width;
	u_int	depth;
	u_int	cmsize;
};
.Ed
.Pp
The
.Va height
and
.Va width
members are counted in pixels.  The
.Va depth
member indicates the number of bits per pixel, and
.Va cmsize
indicates the number of color map entries accessible through
.Dv WSDISPLAYIO_GETCMAP
and
.Dv WSDISPLAYIO_PUTCMAP .
This call is likely to be unavailable on text-only displays.
.It Dv WSDISPLAYIO_GETCMAP Pq Li "struct wsdisplay_cmap"
Retrieve the current color map from the display.  This call needs the
following structure set up beforehand:
.Bd -literal -offset indent
struct wsdisplay_cmap {
	u_int	index;
	u_int	count;
	u_char	*red;
	u_char	*green;
	u_char	*blue;
};
.Ed
.Pp
The
.Va index
and
.Va count
members specify the range of color map entries to retrieve.  The
.Va red ,
.Va green ,
and
.Va blue
members should each point to an array of
.Va count
.Li u_char Ns s .
On return, these will be filled in with the appropriate entries from the
color map.  On all displays that support this call, values range from 0
for minimum intensity to 255 for maximum intensity, even if the display
does not use eight bits internally to represent intensity.
.It Dv WSDISPLAYIO_PUTCMAP Pq Li "struct wsdisplay_cmap"
Change the display's color map.  The argument structure is the same as for
.Dv WSDISPLAYIO_GETCMAP ,
but
.Va red ,
.Va green ,
and
.Va blue
are taken as pointers to the values to use to set the color map.
This call is not available on displays with fixed color maps.
.It Dv WSDISPLAYIO_GVIDEO Pq Li int
Get the current state of the display's video output.  Possible values are:
.Bl -tag -width Dv
.It Dv WSDISPLAYIO_VIDEO_OFF
The display is blanked.
.It Dv WSDISPLAYIO_VIDEO_ON
The display is enabled.
.El
.It Dv WSDISPLAYIO_SVIDEO Pq Li int
Set the state of the display's video output.  See
.Dv WSDISPLAYIO_GVIDEO
above for possible values.
.It Dv WSDISPLAYIO_GCURPOS Pq Li "struct wsdisplay_curpos"
Retrieve the current position of the hardware cursor.  The returned structure
is as follows:
.Bd -literal -offset indent
struct wsdisplay_curpos {
        u_int x, y;
};
.Ed
.Pp
The
.Va x
and
.Va y
members count the number of pixels right and down, respectively, from
the top-left corner of the display to the hot spot of the cursor.
This call is not available on displays without a hardware cursor.
.It Dv WSDISPLAYOP_SCURPOS Pq Li "struct wsdisplay_curpos"
Set the current cursor position.  The argument structure, and its semantics,
are the same as for
.Dv WSDISPLAYIO_GCURPOS .
This call is not avilable on displays without a hardware cursor.
.It Dv WSDISPLAYIO_GCURMAX Pq Li "struct wsdisplay_curpos"
Retrieve the maximum size of cursor supported by the display.  The
.Va x
and
.Va y
members of the returned structure indicate the maximum number of pixel rows
and columns, respectively, in a hardware cursor on this display.
This call is not available on displays without a hardware cursor.
.It Dv WSDISPLAYIO_GCURSOR Pq Li "struct wsdisplay_cursor"
Retrieve some or all of the hardware cursor's attributes.  The argument
structure is as follows:
.Bd -literal -offset indent
struct wsdisplay_cursor {
	u_int	which;
	u_int	enable;
	struct wsdisplay_curpos pos;
	struct wsdisplay_curpos hot;
	struct wsdisplay_cmap cmap;
	struct wsdisplay_curpos size;
	u_char *image;
	u_char *mask;
};
.Pp
.Ed
The
.Va which
member indicates which of the values the application requires to be returned.
It should contain the logical OR of the following flags:
.Bl -tag -width Dv
.It Dv WSDISPLAYIO_CURSOR_DOCUR
Get
.Va enable ,
which indicates whether the cursor is currently displayed (non-zero) or
not (zero).
.It Dv WSDISPLAYIO_CURSOR_DOPOS
Get
.Va pos ,
which indicates the current position of the cursor on the display, as
would be returned by
.Dv WSDISPLAYIO_GCURPOS .
.It Dv WSDISPLAYIO_CURSOR_DOHOT
Get
.Va hot ,
which indicates the location of the
.Dq hot spot
within the cursor.  This is the point on the cursor whose position on the
display is treated as being the position of the cursor by other calls.
Its location is counted in pixels from the top-right corner of the cursor.
.It Dv WSDISPLAYIO_CURSOR_DOCMAP
Get
.Va cmap ,
which indicates the current cursor color map.
Unlike in a call to
.Dv WSDISPLAYIO_GETCMAP ,
.Va cmap
here need not have its
.Va index
and
.Va count
members initialized.  They will be set to 0 and 2 respectively by the call.
This means that
.Va cmap . Ns Va red ,
.Va cmap . Ns Va green ,
and
.Va cmap . Ns Va blue
must each point to at least enough space to hold two
.Li u_char Ns s .
.It Dv WSDISPLAYIO_CURSOR_DOSHAPE
Get
.Va size , image ,
and
.Va mask .
These are, respectively, the dimensions of the cursor in pixels, the
bitmap of set pixels in the cursor and the bitmap of opaque pixels in
the cursor.  The format in which these bitmaps are returned, and hence
the amount of space that must be provided by the application, are
device-dependent.
.It Dv WSDISPLAYIO_CURSOR_DOALL
Get all of the above.
.El
.Pp
The device may elect to return information that was not requested by the user,
so those elements of
.Li "struct wsdisplay_cursor"
which are pointers should be initialized to
.Dv NULL
if not otherwise used.
This call is not available on displays without a hardware cursor.
.It Dv WSDISPLAYIO_SCURSOR Pq Li "struct wsdisplay_cursor"
Set some or all of the hardware cursor's attributes.  The argument structure
is the same as for
.Dv WSDISPLAYIO_GCURSOR .
The
.Va which
member specifies which attributes of the cursor are to be changed.
It should contain the logical OR of the following flags:
.Bl -tag -width Dv
.It Dv WSDISPLAYIO_CURSOR_DOCUR
If
.Va enable
is zero, hide the cursor.  Otherwise, display it.
.It Dv WSDISPLAYIO_CURSOR_DOPOS
Set the cursor's position on the display to
.Va pos ,
the same as
.Dv WSDISPLAYIO_SCURPOS .
.It Dv WSDISPLAYIO_CURSOR_DOHOT
Set the
.Dq hot spot
of the cursor, as defined above, to
.Va hot .
.It Dv WSDISPLAYIO_CURSOR_DOCMAP
Set some or all of the cursor color map based on
.Va cmap .
The
.Va index
and
.Va count
elements of
.Va cmap
indicate which color map entries to set, and the entries themselves come from
.Va cmap . Ns Va red ,
.Va cmap . Ns Va green ,
and
.Va cmap . Ns Va blue .
.It Dv WSDISPLAYIO_CURSOR_DOSHAPE
Set the cursor shape from
.Va size , image ,
and
.Va mask .
See above for their meanings.
.It Dv WSDISPLAYIO_CURSOR_DOALL
Do all of the above.
.El
.Pp
This call is not available on displays without a hardware cursor.
.It Dv WSDISPLAYIO_GMODE Pq Li u_int
Get the current mode of the display.  Possible results include:
.Bl -tag -width Dv
.It Dv WSDISPLAYIO_MODE_EMUL
The display is in emulating (text) mode.
.It Dv WSDISPLAYIO_MODE_MAPPED
The display is in mapped (graphics) mode.
.El
.Pp
.It Dv WSDISPLAYIO_SMODE Pq Li u_int
Set the current mode of the display.  For possible arguments, see
.Dv WSDISPLAYIO_GMODE .
.El
.Sh FILES
.Bl -item
.It
.Pa /dev/ttyE*
Terminal devices (per screen).
.It
.Pa /dev/ttyEcfg
Control device.
.It
.Pa /dev/ttyEstat
Status device.
.It
.Pa /usr/include/dev/wscons/wsconsio.h
.El
.Sh SEE ALSO
.Xr ioctl 2 ,
.Xr ega 4 ,
.Xr pcdisplay 4 ,
.Xr tty 4 ,
.Xr vga 4 ,
.Xr wscons 4 ,
.Xr wsconscfg 8 ,
.Xr wsconsctl 8 ,
.Xr wsfontload 8 ,
.Xr wsdisplay 9
.Sh BUGS
The
.Nm
code currently limits the number of screens on one display to 8.
.Pp
The terms
.Dq wscons
and
.Dq wsdisplay
are not cleanly distinguished in the code and in manual pages.
.Pp
.Dq non-emulating
display devices are not tested.