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 a text terminal or graphics interface.
A display device can have the ability to display characters on it (without the help of an X server), either directly by hardware or through software putting pixel data into the display memory. Such displays are called “emulating”, the
wsdisplay 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.
The
console locator in the configuration line refers to the device's use as the 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 the 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 “emulating” display devices are usable as console.)
The
kbdmux 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
vga(4) and the VAX “smg” display drivers provide this ability.) Screens have different minor device numbers and separate tty instances. One screen possesses the “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 CTRL-ALT-F
n) or an ioctl command issued by a user program. Screens are created and deleted through the
/dev/ttyEcfg control device (preferably using the
wsconscfg(8) utility). Alternatively, the compile-time option
WSDISPLAY_DEFAULTSCREENS=
n will also create (at autoconfiguration time)
n initial screens of the display driver's default type with the system's default terminal emulator.
Kernel options
The following kernel options are available to configure the behavior of the
wsdisplay driver:
options WSDISPLAY_BORDER_COLOR=WSCOL_XXX
Sets the border color at boot time. Possible values are defined in src/sys/dev/wscons/wsdisplayvar.h. Defaults to ‘WSCOL_BLACK'.
options WSDISPLAY_CUSTOM_BORDER
Enables the
WSDISPLAYIO_GBORDER and
WSDISPLAYIO_SBORDER ioctls, which allow the customization of the border color from userland (after boot). See
wsconsctl(8).
options WSDISPLAY_CUSTOM_OUTPUT
Enables the
WSDISPLAYIO_GMSGATTRS and
WSDISPLAYIO_SMSGATTRS ioctls, which allow the customization of the console output and kernel messages from userland (after boot). See
wsconsctl(8).
options WSDISPLAY_DEFAULTSCREENS=N
Sets the number of virtual screens to allocate at boot time. Useful for small root filesystems where the
wsconscfg(8) utility is not wanted.
options WSDISPLAY_SCROLLSUPPORT
Enables scrolling support. The key combinations are LEFT SHIFT + PAGE UP and LEFT SHIFT + PAGE DOWN by default. Please note that this function may not work under the system console and is available depending on the framebuffer you are using.
Ioctls
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_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 (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 (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.
WSDISPLAYOP_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:
WSDISPLAYIO_CURSOR_DOCUR
Get enable, which indicates whether the cursor is currently displayed (non-zero) or not (zero).
WSDISPLAYIO_CURSOR_DOPOS
Get pos, which indicates the current position of the cursor on the display, as would be returned by WSDISPLAYIO_GCURPOS.
WSDISPLAYIO_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-right corner of the cursor.
WSDISPLAYIO_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.
WSDISPLAYIO_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.
WSDISPLAYIO_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:
WSDISPLAYIO_CURSOR_DOCUR
If enable is zero, hide the cursor. Otherwise, display it.
WSDISPLAYIO_CURSOR_DOPOS
Set the cursor's position on the display to pos, the same as WSDISPLAYIO_SCURPOS.
WSDISPLAYIO_CURSOR_DOHOT
Set the “hot spot” of the cursor, as defined above, to hot.
WSDISPLAYIO_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.
WSDISPLAYIO_CURSOR_DOSHAPE
Set the cursor shape from size, image, and mask. See above for their meanings.
WSDISPLAYIO_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_LINEBYTES (u_int)
Get the number of bytes per row, which may be the same as the number of pixels.
WSDISPLAYIO_GMSGATTRS (struct wsdisplay_msgattrs)
Get the attributes (colors and flags) used to print console messages, including separate fields for default output and kernel output. The returned structure is as follows:
struct wsdisplay_msgattrs {
int default_attrs, default_bg, default_fg;
int kernel_attrs, kernel_bg, kernel_fg;
};
The
default_attrs and
kernel_attrs variables are a combination of
WSATTR_* bits, and specify the attributes used to draw messages. The
default_bg,
default_fg,
kernel_bg and
kernel_fg variables specify the colors used to print messages, being ‘_bg' for the background and ‘_fg' for the foreground; their values are one of all the
WSCOL_* macros available.
WSDISPLAYIO_SMSGATTRS (struct wsdisplay_msgattrs)
Set the attributes (colors and flags) used to print console messages, including separate fields for default output and kernel output. The argument structure is the same as for WSDISPLAYIO_GMSGATTRS.
WSDISPLAYIO_GBORDER (u_int)
Retrieve the color of the screen border. This number corresponds to an ANSI standard color.
WSDISPLAYIO_SBORDER (u_int)
Set the color of the screen border, if applicable. This number corresponds to an ANSI standard color. Not all drivers support this feature.
WSDISPLAYIO_GETWSCHAR (struct wsdisplay_char)
Gets a single character from the screen, specified by its position. The structure used is as follows:
struct wsdisplay_char {
int row, col;
uint16_t letter;
uint8_t background, foreground;
char flags;
};
The
row and
col parameters are used as input; the rest of the structure is filled by the ioctl and is returned to you.
letter is the ASCII code of the letter found at the specified position,
background and
foreground are its colors and
flags is a combination of ‘WSDISPLAY_CHAR_BRIGHT' and/or ‘WSDISPLAY_CHAR_BLINK'.
WSDISPLAYIO_PUTWSCHAR (struct wsdisplay_char)
Puts a character on the screen. The structure has the same meaning as described in WSDISPLAY_GETWSCHAR, although all of its fields are treated as input.
WSDISPLAYIO_SSPLASH (u_int)
Toggle the splash screen. This call is only available with the SPLASHSCREEN kernel option.
WSDISPLAYIO_SPROGRESS (u_int)
Update the splash animation. This call is only available with the SPLASHSCREEN and SPLASHSCREEN_PROGRESS kernel options.