WSDISPLAY(4)

NAME
wsdisplay - generic display device support in wscons

SYNOPSIS
wsdisplay* at ...
option WSDISPLAY_DEFAULTSCREENS=N

DESCRIPTION
The wsdisplay driver is an abstraction layer for display devices within the wscons(4) framework. It attaches to the hardware specific display device driver and makes it available as text terminal or graphics interface.

Display devices have the ability to display characters on them (without help of an X server), either directly by hardware or through software drawing pixel data into the display memory. The wsdisplay driver will connect a terminal emulation module and provide a tty-like software interface.

The 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.

The mux locator in the configuration line refers to the wsmux(4) that will be used to get keyboard events. If this locator is -1 no mux will be used.

The logical unit of an independent contents displayed on a display (sometimes referred to as “virtual terminal”) is called a “screen” here. If the underlying device driver supports it, multiple screens can be used on one display. (As of this writing, only the lcd(4) and vga(4) display drivers provide this ability.) Screens have different minor device numbers and separate tty instances. One screen possesses the “focus”, this means it is displayed on the display 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 CTL-ALT-Fn) or an ioctl command issued by a user program. Screens are set up or deleted through the /dev/ttyCcfg control device (preferably using the wsconscfg(8) utility). Alternatively, the compile-time option WSDISPLAY_DEFAULTSCREENS=N will set up N screens of the display driver's default type and using the system's default terminal emulator at autoconfiguration time.

In addition and with help from backend drivers the following features are also provided:

•   Loading, deleting and listing the loaded fonts.

•   Browsing backwards in the screen output, the size of the buffer for saved text is defined by the particular hardware driver.

•   Blanking the screen by timing out on inactivity in the screen holding the input focus. Awakening activities consist of:

    •   pressing any keys on the keyboard;
    •   moving or clicking the mouse;
    •   any output to the screen.

    Blanking the screen is usually done by disabling the horizontal sync signal on video output, but may also include blanking the vertical sync in which case most monitors go into power saving mode. See wsconsctl(8) for controlling variables.

Consult the back-end drivers' documentation for which features are supported for each particular hardware type.

  IOCTL INTERFACE
The following ioctl(2) calls are provided by the wsdisplay driver or by devices which use it. Their definitions are found in <dev/wscons/wsconsio.h>.

WSDISPLAYIO_GTYPE (u_int)
    Retrieve the type of the display. The list of types is in <dev/wscons/wsconsio.h>.

WSDISPLAYIO_GINFO (struct wsdisplay_fbinfo)
    Retrieve basic information about a framebuffer display. The returned structure is as follows:

        struct wsdisplay_fbinfo {
                u_int   height;
                u_int   width;
                u_int   depth;
                u_int   cmsize;
        };

    The height and width members are counted in pixels. The depth member indicates the number of bits per pixel, and cmsize indicates the number of color map entries accessible through WSDISPLAYIO_GETCMAP and WSDISPLAYIO_PUTCMAP. This call is likely to be unavailable on text-only displays.

WSDISPLAYIO_GETCMAP (struct wsdisplay_cmap)
    Retrieve the current color map from the display. This call needs the following structure set up beforehand:

        struct wsdisplay_cmap {
                u_int   index;
                u_int   count;
                u_char  *red;
                u_char  *green;
                u_char  *blue;
        };

    The index and count members specify the range of color map entries to retrieve. The red, green, and blue members should each point to an array of count u_chars. 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.

WSDISPLAYIO_PUTCMAP (struct wsdisplay_cmap)
    Change the display's color map. The argument structure is the same as for WSDISPLAYIO_GETCMAP, but red, green, and 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.

WSDISPLAYIO_GVIDEO (u_int)
    Get the current state of the display's video output. Possible values are:

    WSDISPLAYIO_VIDEO_OFF
        The display is blanked.

    WSDISPLAYIO_VIDEO_ON
        The display is enabled.

WSDISPLAYIO_SVIDEO (u_int)
    Set the state of the display's video output. See WSDISPLAYIO_GVIDEO above for possible values.

WSDISPLAYIO_GCURPOS (struct wsdisplay_curpos)
    Retrieve the current position of the hardware cursor. The returned structure is as follows:

        struct wsdisplay_curpos {
                u_int x, y;
        };

    The x and 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.

WSDISPLAYIO_SCURPOS (struct wsdisplay_curpos)
    Set the current cursor position. The argument structure, and its semantics, are the same as for WSDISPLAYIO_GCURPOS. This call is not available on displays without a hardware cursor.

WSDISPLAYIO_GCURMAX (struct wsdisplay_curpos)
    Retrieve the maximum size of cursor supported by the display. The x and 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.

WSDISPLAYIO_GCURSOR (struct wsdisplay_cursor)
    Retrieve some or all of the hardware cursor's attributes. The argument structure is as follows:

        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;
        };

    The which member indicates which of the values the application requires to be returned. It should contain the logical OR of the following flags:

    WSDISPLAY_CURSOR_DOCUR
        Get enable, which indicates whether the cursor is currently displayed (non-zero) or not (zero).

    WSDISPLAY_CURSOR_DOPOS
        Get pos, which indicates the current position of the cursor on the display, as would be returned by WSDISPLAYIO_GCURPOS.

    WSDISPLAY_CURSOR_DOHOT
        Get hot, which indicates the location of the “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-left corner of the cursor.

    WSDISPLAY_CURSOR_DOCMAP
        Get cmap, which indicates the current cursor color map. Unlike in a call to WSDISPLAYIO_GETCMAP, cmap here need not have its index and count members initialized. They will be set to 0 and 2 respectively by the call. This means that cmap.red, cmap.green, and cmap.blue must each point to at least enough space to hold two u_chars.

    WSDISPLAY_CURSOR_DOSHAPE
        Get size, image, and 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.

    WSDISPLAY_CURSOR_DOALL
        Get all of the above.

    The device may elect to return information that was not requested by the user, so those elements of struct wsdisplay_cursor which are pointers should be initialized to NULL if not otherwise used. This call is not available on displays without a hardware cursor.

WSDISPLAYIO_SCURSOR (struct wsdisplay_cursor)
    Set some or all of the hardware cursor's attributes. The argument structure is the same as for WSDISPLAYIO_GCURSOR. The which member specifies which attributes of the cursor are to be changed. It should contain the logical OR of the following flags:

    WSDISPLAY_CURSOR_DOCUR
        If enable is zero, hide the cursor. Otherwise, display it.

    WSDISPLAY_CURSOR_DOPOS
        Set the cursor's position on the display to pos, the same as WSDISPLAYIO_SCURPOS.

    WSDISPLAY_CURSOR_DOHOT
        Set the “hot spot” of the cursor, as defined above, to hot.

    WSDISPLAY_CURSOR_DOCMAP
        Set some or all of the cursor color map based on cmap. The index and count elements of cmap indicate which color map entries to set, and the entries themselves come from cmap.red, cmap.green, and cmap.blue.

    WSDISPLAY_CURSOR_DOSHAPE
        Set the cursor shape from size, image, mask. See above for their meanings.

    WSDISPLAY_CURSOR_DOALL
        Do all of the above.

    This call is not available on displays without a hardware cursor.

WSDISPLAYIO_GMODE (u_int)
    Get the current mode of the display. Possible results include:

    WSDISPLAYIO_MODE_EMUL
        The display is in emulating (text) mode.

    WSDISPLAYIO_MODE_MAPPED
        The display is in mapped (graphics) mode.

    WSDISPLAYIO_MODE_DUMBFB
        The display is in mapped (frame buffer) mode.

WSDISPLAYIO_SMODE (u_int)
    Set the current mode of the display. For possible arguments, see WSDISPLAYIO_GMODE.

WSDISPLAYIO_GBURNER (struct wsdisplay_burner)
    Retrieves the state of the screen burner. The returned structure is as follows:

        struct wsdisplay_burner {
                u_int   off;
                u_int   on;
                u_int   flags;
        };

    The off member contains the inactivity time before the screen is turned off, in milliseconds. The on member contains the time before the screen is turned back on, in milliseconds. The flags member contains a logical OR of the following flags:

    WSDISPLAY_BURN_VBLANK
        When turning the display off, disable the vertical synchronization signal.

    WSDISPLAY_BURN_KBD
        Monitor keyboard activity.

    WSDISPLAY_BURN_MOUSE
        Monitor mouse activity (this only works for mice using the wsmouse(4) driver).

    WSDISPLAY_BURN_OUTPUT
        Monitor display output activity.

    If none of the activity source flags are set, the screen burner is disabled.

WSDISPLAYIO_SBURNER (struct wsdisplay_burner)
    Sets the state of the screen burner. The argument structure, and its semantics, are the same as for WSDISPLAYIO_GBURNER.

WSDISPLAYIO_WSMOUSED (struct wscons_event)
    This call is used by the wsmoused(8) daemon to inject mouse events gathered from serial mice, as well as various control events.

WSDISPLAYIO_GETPARAM (struct wsdisplay_param)
    Retrieves the state of a display parameter. This call needs the following structure set up beforehand:

        struct wsdisplay_param {
                int param;
                int min, max, curval;
                int reserved[4];
        };

    The param member should be set with the parameter to be returned. The following parameters are supported:

    WSDISPLAYIO_PARAM_BACKLIGHT
        The intensity of the display backlight (usually on laptop computers).

    WSDISPLAYIO_PARAM_BRIGHTNESS
        The brightness level.

    WSDISPLAYIO_PARAM_CONTRAST
        The contrast level.

    On return, min and max specify the allowed range for the value, while curval specifies the current setting. Not all parameters are supported by all display drivers.

WSDISPLAYIO_SETPARAM (struct wsdisplay_param)
    Sets a display parameter. The argument structure is the same as for WSDISPLAYIO_GETPARAM, with the param and curval members filled in. Not all parameters are supported by all display drivers.

WSDISPLAYIO_LINEBYTES (u_int)
    Get the number of bytes per row when the device is in WSDISPLAYIO_MODE_DUMBFB mode.

FILES
/dev/tty[C-F]*
    terminal devices (per screen)
/dev/tty[C-F]cfg
    control device (per screen)
/usr/include/dev/wscons/wsconsio.h

SEE ALSO
intro(4), tty(4), wscons(4), wsmux(4), wsconscfg(8), wsconsctl(8), wsfontload(8)

BUGS
The wsdisplay code currently limits the number of screens on one display to 8.

The terms “wscons” and “wsdisplay” are not cleanly distinguished in the code and in manual pages.