illumos: manual page: visual

VISUAL_IO(4I) 4I VISUAL_IO(4I)

NAME

visual_io - illumos VISUAL I/O control operations

SYNOPSIS

#include <sys/visual_io.h>

DESCRIPTION

The illumos VISUAL environment defines a small set of ioctls for
controlling graphics and imaging devices.

The VIS_GETIDENTIFIER ioctl is mandatory and must be implemented in device
drivers for graphics devices using the illumos VISUAL environment. The
VIS_GETIDENTIFIER ioctl is defined to return a device identifier from the
device driver. This identifier must be a uniquely-defined string.

There are two additional sets of ioctls. One supports mouse tracking via
hardware cursor operations. Use of this set is optional, however, if a
graphics device has hardware cursor support and implements these ioctls,
the mouse tracking performance is improved. The remaining set supports the
device acting as the system console device. Use of this set is optional,
but if a graphics device is to be used as the system console device, it
must implement these ioctls.

The VISUAL environment also defines interfaces for non-ioctl entry points
into the driver that the illumos operating environment calls when it is
running in standalone mode (for example, when using a stand-alone debugger,
entering the PROM monitor, or when the system panicking). These are also
known as "Polled I/O" entry points, which operate under an an explicit set
of restrictions, described below.

IOCTLS

VIS_GETIDENTIFIER This ioctl(2) returns an identifier string to uniquely
identify a device used in the illumos VISUAL
environment. This is a mandatory ioctl and must return
a unique string. We suggest that the name be formed as
<companysymbol><devicetype>. For example, the cgsix(4D)
driver returns SUNWcg6.

VIS_GETIDENTIFIER takes a vis_identifier structure as
its parameter. This structure has the form:

#define VIS_MAXNAMELEN 128
struct vis_identifier {
char name[VIS_MAXNAMELEN];
};

VIS_GETCURSOR
VIS_SETCURSOR These ioctls fetch and set various cursor attributes,
using the vis_cursor structure.

struct vis_cursorpos {
short x; /* cursor x coordinate */
short y; /* cursor y coordinate */
};

struct vis_cursorcmap {
int version; /* version */
int reserved;
/* red color map elements */
unsigned char *red;
/* green color map elements */
unsigned char *green;
/* blue color map elements */
unsigned char *blue;
};

#define VIS_CURSOR_SETCURSOR 0x01 /* set cursor */
/* set cursor position */
#define VIS_CURSOR_SETPOSITION 0x02
/* set cursur hot spot */
#define VIS_CURSOR_SETHOTSPOT 0x04
/* set cursor colormap */
#define VIS_CURSOR_SETCOLORMAP 0x08
/* set cursor shape */
#define VIS_CURSOR_SETSHAPE 0x10
#define VIS_CURSOR_SETALL \
(VIS_CURSOR_SETCURSOR | VIS_CURSOR_SETPOSITION | \
VIS_CURSOR_SETHOTSPOT | VIS_CURSOR_SETCOLORMAP | \
VIS_CURSOR_SETSHAPE)

struct vis_cursor {
short set; /* what to set */
short enable; /* cursor on/off */
struct vis_cursorpos pos; /* cursor position */
struct vis_cursorpos hot; /* cursor hot spot */
struct vis_cursorcmap cmap; /* color map info */
/* cursor bitmap size */
struct vis_cursorpos size;
char *image; /* cursor image bits */
char *mask; /* cursor mask bits */
};

The vis_cursorcmap structure should contain pointers to
two elements, specifying the red, green, and blue values
for foreground and background.

VIS_SETCURSORPOS
VIS_MOVECURSOR These ioctls fetch and move the current cursor position,
using the vis_cursorpos structure.

Console Optional Ioctls

The following ioctl sets are used by graphics drivers that are part of the
system console device. All of the ioctls must be implemented to be a
console device. In addition, if the system does not have a prom or the
prom goes away during boot, the special standalone ioctls (listed below)
must also be implemented.

The coordinate system for the console device places 0,0 at the upper left
corner of the device, with rows increasing toward the bottom of the device
and columns increasing from left to right.

VIS_PUTCMAP
VIS_GETCMAP Set or get color map entries.

The argument is a pointer to a vis_cmap structure, which
contains the following fields:

struct vis_cmap {
int index;
int count;
uchar_t *red;
uchar_t *green;
uchar_t *blue;
}

index is the starting index in the color map where you
want to start setting or getting color map entries.

count is the number of color map entries to set or get.
It also is the size of the red, green, and blue color
arrays.

*red, *green, and *blue are pointers to unsigned
character arrays which contain the color map info to set
or where the color map info is placed on a get.

VIS_DEVINIT Initializes the graphics driver as a console device.

The argument is a pointer to a vis_devinit structure.
The graphics driver is expected to allocate any local
state information needed to be a console device and fill
in this structure.

struct vis_devinit {
int version;
screen_size_t width;
screen_size_t height;
screen_size_t linebytes;
unit_t size;
int depth;
short mode;
struct vis_polledio *polledio;
vis_modechg_cb_t modechg_cb;
struct vis_modechg_arg *modechg_arg;
};

version is the version of this structure and should be
set to VIS_CONS_REV.

width and height are the width and height of the device.
If mode (see below) is VIS_TEXT then width and height
are the number of characters wide and high of the
device. If mode is VIS_PIXEL then width and height are
the number of pixels wide and high of the device.

linebytes is the number of bytes per line of the device.

size is the total size of the device in pixels.

depth is the pixel depth in device bits. Currently
supported depths are: 1, 4, 8 and 24.

mode is the mode of the device. Either VIS_PIXEL (data
to be displayed is in bitmap format) or VIS_TEXT (data
to be displayed is in ascii format).

polledio is used to pass the address of the structure
containing the standalone mode polled I/O entry points
to the device driver back to the terminal emulator. The
vis_polledio interfaces are described in the Console
Standalone Entry Points section of this manpage. These
entry points are where the operating system enters the
driver when the system is running in standalone mode.
These functions perform identically to the
VIS_CONSDISPLAY, VIS_CONSCURSOR, and VIS_CONSCOPY
ioctls, but are called directly by the illumos operating
environment and must operate under a very strict set of
assumptions.

modechg_cb is a callback function passed from the
terminal emulator to the framebuffer driver which the
frame-buffer driver must call whenever a video mode
change event occurs that changes the screen height,
width or depth. The callback takes two arguments, an
opaque handle, modechg_arg, and the address of a
vis_devinit struct containing the new video mode
information.

modechg_arg is an opaque handle passed from the terminal
emulator to the driver, which the driver must pass back
to the terminal emulator as an argument to the
modechg_cb function when the driver notifies the
terminal emulator of a video mode change.

VIS_DEVFINI Tells the graphics driver that it is no longer the
system console device. There is no argument to this
ioctl. The driver is expected to free any locally kept
state information related to the console.

VIS_CONSCURSOR Describes the size and placement of the cursor on the
screen. The graphics driver is expected to display or
hide the cursor at the indicated position.

The argument is a pointer to a vis_conscursor structure
which contains the following fields:

struct vis_conscursor {
screen_pos_t row;
screen_pos_t col;
screen_size_t width;
screen_size_t height
color_t fg_color;
color_t bg_color;
short action;
};

row and col are the first row and column (upper left
corner of the cursor).

width and height are the width and height of the cursor.

If mode in the VIS_DEVINIT ioctl is set to VIS_PIXEL,
then col, row, width and height are in pixels. If mode
in the VIS_DEVINIT ioctl was set to VIS_TEXT, then col,
row, width and height are in characters.

fg_color and bg_color are the foreground and background
color map indexes to use when the action (see below) is
set to VIS_DISPLAY_CURSOR.

action indicates whether to display or hide the cursor.
It is set to either VIS_HIDE_CURSOR or
VIS_DISPLAY_CURSOR.

VIS_CONSDISPLAY Display data on the graphics device. The graphics
driver is expected to display the data contained in the
vis_display structure at the specified position on the
console.

The vis_display structure contains the following fields:

struct vis_display {
screen_pos_t row;
screen_pos_t col;
screen_size_t width;
screen_size_t height;
uchar_t *data;
color_t fg_color;
color_t bg_color;
};

row and col specify at which starting row and column the
date is to be displayed. If mode in the VIS_DEVINIT
ioctl was set to VIS_TEXT, row and col are defined to be
a character offset from the starting position of the
console device. If mode in the VIS_DEVINIT ioctl was
set to VIS_PIXEL, row and col are defined to be a pixel
offset from the starting position of the console device.

width and height specify the size of the data to be
displayed. If mode in the VIS_DEVINIT ioctl was set to
VIS_TEXT, width and height define the size of data as
rectangle that is width characters wide and height
characters high. If mode in the VIS_DEVINIT ioctl was
set to VIS_PIXEL, width and height define the size of
data as a rectangle that is width pixels wide and height
pixels high.

*data is a pointer to the data to be displayed on the
console device. If mode in the VIS_DEVINIT ioctl was
set to VIS_TEXT, data is an array of ASCII characters to
be displayed on the console device. The driver must
break these characters up appropriately and display it
in the rectangle defined by row, col, width, and height.
If mode in the VIS_DEVINIT ioctl was set to VIS_PIXEL,
data is an array of bitmap data to be displayed on the
console device. The driver must break this data up
appropriately and display it in the retangle defined by
row, col, width, and height.

The fg_color and bg_color fields define the foreground
and background color map indexes to use when displaying
the data. fb_color is used for "on" pixels and bg_color
is used for "off" pixels.

VIS_CONSCOPY Copy data from one location on the device to another.
The driver is expected to copy the specified data. The
source data should not be modified. Any modifications
to the source data should be as a side effect of the
copy destination overlapping the copy source.

The argument is a pointer to a vis_copy structure which
contains the following fields:

struct vis_copy {
screen_pos_t s_row;
screen_pos_t s_col;
screen_pos_t e_row;
screen_pos_t e_col;
screen_pos_t t_row;
screen_pos_t t_col;
short direction;
};

s_row, s_col, e_row, and e_col define the source
rectangle of the copy. s_row and s_col are the upper
left corner of the source rectangle. e_row and e_col
are the lower right corner of the source rectangle. If
mode in the VIS_DEVINIT ioctl() was set to VIS_TEXT,
s_row, s_col, e_row, and e_col are defined to be
character offsets from the starting position of the
console device. If mode in the VIS_DEVINIT ioctl() was
set to VIS_PIXEL, s_row, s_col, e_row, and e_col are
defined to be pixel offsets from the starting position
of the console device.

t_row and t_col define the upper left corner of the
destination rectangle of the copy. The entire rectangle
is copied to this location. If mode in the VIS_DEVINIT
ioctl was set to VIS_TEXT, t_row, and t_col are defined
to be character offsets from the starting position of
the console device. If mode in the VIS_DEVINIT ioctl
was set to VIS_PIXEL, t_row, and t_col are defined to be
pixel offsets from the starting position of the onssole
device.

direction specifies which way to do the copy. If
direction is VIS_COPY_FORWARD the graphics driver should
copy data from position (s_row, s_col) in the source
rectangle to position (t_row, t_col) in the destination
rectangle. If direction is VIS_COPY_BACKWARDS the
graphics driver should copy data from position (e_row,
e_col) in the source rectangle to position
(t_row+(e_row-s_row), t_col+(e_col-s_col)) in the
destination rectangle.

Console Standalone Entry Points (Polled I/O Interfaces)
Console standalone entry points are necessary only if the driver is
implementing console-compatible extensions. All console vectored
standalone entry points must be implemented along with all console-related
ioctls if the console extension is implemented.

struct vis_polledio {
struct vis_polledio_arg *arg;
void (*display)(vis_polledio_arg *, struct vis_consdisplay *);
void (*copy)(vis_polledio_arg *, struct vis_conscopy *);
void (*cursor)(vis_polledio_arg *, struct vis_conscursor *);
};

The vis_polledio structure is passed from the driver to the illumos
operating environment, conveying the entry point addresses of three
functions which perform the same operations of their similarly named ioctl
counterparts. The rendering parameters for each entry point are derived
from the same structure passed as the respective ioctl. See the Console
Optional Ioctls section of this manpage for an explanation of the specific
function each of the entry points, display(), copy(), and cursor() are
required to implement. In addition to performing the prescribed function
of their ioctl counterparts, the standalone vectors operate in a special
context and must adhere to a strict set of rules. The polled I/O vectors
are called directly whenever the system is quisced (running in a limited
context) and must send output to the display. Standalone mode describes
the state in which the system is running in single-threaded mode and only
one processor is active. illumos operating environment services are
stopped, along with all other threads on the system, prior to entering any
of the polled I/O interfaces. The polled I/O vectors are called when the
system is running in a standalone debugger, when executing the PROM monitor
(OBP) or when panicking.

The following restrictions must be observed in the polled I/O functions:

1. The driver must not allocate memory.

2. The driver must not wait on mutexes.

3. The driver must not wait for interrupts.

4. The driver must not call any DDI or LDI services.

5. The driver must not call any system services.

The system is single-threaded when calling these functions, meaning that
all other threads are effectively halted. Single-threading makes mutexes
(which cannot be held) easier to deal with, so long as the driver does not
disturb any shared state. See Writing Device Drivers for more information
about implementing polled I/O entry points.

NOTES