VISUAL_IO(4I) Ioctl Requests VISUAL_IO(4I)

visual_io — illumos VISUAL I/O control operations

#include <sys/visual_io.h>

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 explicit set of restrictions, described below.

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⟩.

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];
};

 
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 cursor 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.

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

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.

 
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.

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: , , and .

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.

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.

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.

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 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.

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 () 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 console 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 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, (), (), and () 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 quiesced (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.

ioctl(2)

Writing Device Drivers.

On SPARC systems, compatible drivers supporting the kernel terminal emulator should export the tem-support DDI property. tem-support indicates that the driver supports the kernel terminal emulator. By exporting tem-support it's possible to avoid premature handling of an incompatible driver.

This DDI property, set to 1, means driver is compatible with the console kernel framebuffer interface.
March 13, 2022 OmniOS