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SYSCONS(4)            DragonFly Kernel Interfaces Manual            SYSCONS(4)


syscons, sc - the console driver


options MAXCONS=N options SC_ALT_MOUSE_IMAGE options SC_DISABLE_DDBKEY options SC_DISABLE_REBOOT options SC_HISTORY_SIZE=N options SC_MOUSE_CHAR=C options SC_NO_CUTPASTE options SC_NO_FONT_LOADING options SC_NO_HISTORY options SC_NO_SYSMOUSE options SC_PIXEL_MODE options SC_TWOBUTTON_MOUSE options SC_NORM_ATTR=_attribute_ options SC_NORM_REV_ATTR=_attribute_ options SC_KERNEL_CONS_ATTR=_attribute_ options SC_KERNEL_CONS_REV_ATTR=_attribute_ options SC_BORDER_COLOR=_attribute_ options SC_DFLT_FONT makeoptions SC_DFLT_FONT=_font_name_ device sc0 at isa? [flags flags]


The syscons driver provides multiple virtual terminals. It resembles the SCO color console driver. The syscons driver is implemented on top of the keyboard driver (atkbd(4)) and the video card drivers (amdgpu(4), i915(4), radeon(4), or vga(4)). Please see DRIVER CONFIGURATION below on how to make the console work with amdgpu(4), i915(4) or radeon(4). There can be only one syscons device defined in the system. Virtual Terminals The syscons driver provides multiple virtual terminals which appear as if they were separate terminals. One virtual terminal is considered current and exclusively occupies the screen and the keyboard; the other virtual terminals are placed in the background. In order to use virtual terminals, they must be individually marked ``on'' in /etc/ttys so that getty(8) will recognize them to be active and run login(1) to let the user log in to the system. By default, only the first eight virtual terminals are activated in /etc/ttys. You press the Alt key and a switch key to switch between virtual terminals. The following table summarizes the correspondence between the switch key and the virtual terminal. Alt-F1 ttyv0 Alt-F7 ttyv6 Shift-Alt-F1 ttyv10 Alt-F2 ttyv1 Alt-F8 ttyv7 Shift-Alt-F2 ttyv11 Alt-F3 ttyv2 Alt-F9 ttyv8 Shift-Alt-F3 ttyv12 Alt-F4 ttyv3 Alt-F10 ttyv9 Shift-Alt-F4 ttyv13 Alt-F5 ttyv4 Alt-F11 ttyv10 Shift-Alt-F5 ttyv14 Alt-F6 ttyv5 Alt-F12 ttyv11 Shift-Alt-F6 ttyv15 You can also use the ``nscr'' key (usually the PrintScreen key on the AT Enhanced keyboard) to cycle available virtual terminals. The default number of available virtual terminals is 16. This can be changed with the kernel configuration option MAXCONS (see below). Note that the X server usually requires a virtual terminal for display purposes, so at least one terminal must be left unused by getty(8) so that it can be used by the X server. Key Definitions and Function Key Strings The syscons driver, in conjunction with the keyboard driver, allows the user to change key definitions and function key strings. The kbdcontrol(1) command will load a key definition file (known as ``keymap'' file), dump the current keymap, and assign a string to a function key. See keyboard(4) and kbdmap(5) for the keymap file. You may want to set the keymap variable in /etc/rc.conf.local to the desired keymap file so that it will be automatically loaded when the system starts up. Software Font For most modern video cards, e.g. VGA, the syscons driver and the video card driver allow the user to change the font used on the screen. The vidcontrol(1) command can be used to load a font file from /usr/share/syscons/fonts. The font comes in various sizes: 8x8, 8x14 and 8x16. The 8x16 font is typically used for the VGA card in the 80-column-by-25-line mode. Other video modes may require different font sizes. It is better to always load all three sizes of the same font. You may set font8x8, font8x14 and font8x16 variables in /etc/rc.conf to the desired font files so that they will be automatically loaded when the system starts up. Optionally you can specify a particular font file as the default. See the SC_DFLT_FONT option below. Screen Map If your video card does not support software fonts, you may still be able to achieve a similar effect by re-mapping the font built into your video card. Use vidcontrol(1) to load a screen map file which defines the mapping between character codes. Mouse Support and Copy-and-Paste You can use your mouse to copy text on the screen and paste it as if it was typed by hand. You must be running the mouse daemon moused(8) and enable the mouse cursor in the virtual terminal via vidcontrol(1). Pressing mouse button 1 (usually the left button) will start selection. Releasing button 1 will end the selection process. The selected text will be marked by inverting foreground and background colors. You can press button 3 (usually the right button) to extend the selected region. The selected text is placed in the copy buffer and can be pasted at the cursor position by pressing button 2 (usually the middle button) as many times as you like. If your mouse has only two buttons, you may want to use the SC_TWOBUTTON_MOUSE option below to make the right button to paste the text. Alternatively you can make the mouse daemon emulate the middle button. See the man page for moused(8) for more details. Back Scrolling The syscons driver allows the user to browse the output which has ``scrolled off'' the top of the screen. Press the ``slock'' key (usually ScrllLock / Scroll Lock or Pause on many keyboards) and the terminal is in the ``scrollback'' mode. It is indicated by the Scroll Lock LED. Use the arrow keys, the Page Up/Down keys and the Home/End keys to scroll buffered terminal output. Press the ``slock'' key again to get back to the normal terminal mode. The size of the scrollback buffer can be set by the SC_HISTORY_SIZE option described below. Screen Saver The syscons driver can be made to put up the screen saver if the current virtual terminal is idle, that is, the user is not typing on the keyboard nor moving the mouse. See splash(4) and vidcontrol(1) for more details.


Loader Tunables The following tunables are available and can be set in loader.conf(5). kern.kms_console Setting this tunable to 0 disables experimental framebuffer support in conjunction with the amdgpu(4), i915(4) or radeon(4) drivers. It is 1 by default. kern.kms_columns The number of columns to use in conjunction with the amdgpu(4), i915(4) and radeon(4) drivers. The font size is scaled to match the requested number of columns. This requires kern.kms_console to be set to 1. By default, syscons tries to find a more or less pleasant looking default. Setting kern.kms_columns to a negative value turns off scaling. Please note that ttyv0 is restricted to 160 columns and any setting of kern.kms_columns resulting in a higher number of columns will be ignored for ttyv0, but applied to other virtual terminals. Sysctl Variables The following sysctl(8) variable is available and can be either set via sysctl.conf(5) or from the command line. kern.syscons_async Set to 1 to enable asynchronous bulk framebuffer updates. It is intended to help with sound(4) stuttering when a high resolution syscons scrolls during playback. It is not enabled by default because on certain machines it has led to subtle issues with for example ddb(4). Kernel Configuration Options The following kernel configuration options control the syscons driver. MAXCONS=N This option sets the number of virtual terminals to N. The default value is 16. SC_ALT_MOUSE_IMAGE This option selects the alternative way of displaying the mouse cursor in the virtual terminal. It may be expensive for some video cards to draw the arrow-shaped cursor, and you may want to try this option. However, the appearance of the alternative mouse cursor may not be very appealing. Note that if you use the SC_NO_FONT_LOADING option then you must also use this option if you wish to be able to use the mouse. SC_DISABLE_DDBKEY This option disables the ``debug'' key combination (by default, it is Alt-Esc, or Ctl-PrintScreen). It will prevent users from entering the kernel debugger (DDB) by pressing the key combination. DDB will still be invoked when the kernel panics or hits a break point if it is included in the kernel. SC_DISABLE_REBOOT This option disables the ``reboot'' key (by default, it is Ctl-Alt-Del), so that the casual user may not accidentally reboot the system. SC_HISTORY_SIZE=N Sets the size of back scroll buffer to N lines. The default value is 100. SC_MOUSE_CHAR=C Unless the SC_ALT_MOUSE_IMAGE option above is specified, the syscons driver reserves four consecutive character codes in order to display the mouse cursor in the virtual terminals in some systems. This option specifies the first character code to C to be used for this purpose. The default value is 0xd0. A good candidate is 0x03. SC_PIXEL_MODE Adds support for pixel (raster) mode console. This mode is useful on some laptop computers, but less so on most other systems, and it adds substantial amount of code to syscons. If this option is NOT defined, you can reduce the kernel size a lot. SC_TWOBUTTON_MOUSE If you have a two button mouse, you may want to add this option to use the right button of the mouse to paste text. See Mouse Support and Copy-and-Paste above. SC_NORM_ATTR=_attribute_ SC_NORM_REV_ATTR=_attribute_ SC_KERNEL_CONS_ATTR=_attribute_ SC_KERNEL_CONS_REV_ATTR=_attribute_ SC_BORDER_COLOR=_attribute_ These options will set the default colors. Available colors are defined in <machine/pc/display.h>. See EXAMPLES below. SC_DFLT_FONT This option will specify the default font. Available fonts are: iso, iso2, koi8-r, koi8-u, cp437, cp850, cp865, cp866 and cp866u. 16-line, 14-line and 8-line font data will be compiled in. Without this option, the syscons driver will use whatever font is already loaded in the video card, unless you explicitly load a software font at startup. See EXAMPLES below. The following options will remove some features from the syscons driver and save kernel memory. SC_NO_CUTPASTE This option disables ``copy and paste'' operation in virtual terminals. SC_NO_FONT_LOADING The syscons driver can load software fonts on some video cards. This option removes this feature. Note that if you still wish to use the mouse with this option then you must also use the SC_ALT_MOUSE_IMAGE option. SC_NO_HISTORY This option disables back-scrolling in virtual terminals. SC_NO_SYSMOUSE This option removes mouse support in the syscons driver. The mouse daemon moused(8) will fail if this option is defined. This option implies the SC_NO_CUTPASTE option too. Driver Flags The following driver flags can be used to control the syscons driver. They can be set in the kernel configuration file. 0x0100 (AUTODETECT_KBD) This option instructs the syscons driver to periodically scan for a keyboard device if it is not currently attached to one. Otherwise, the driver only probes for a keyboard once during bootup.


The following ioctl(2) commands are defined for the syscons driver in <sys/consio.h>. KDGETMODE int *mode KDSETMODE int *mode Get or set the mode of the current (virtual) console. The mode can be one of: KD_TEXT same as KD_TEXT0 KD_TEXT0 Text mode, restore fonts and palette KD_GRAPHICS Graphics mode KD_TEXT1 Text mode, don't restore fonts and palette KD_PIXEL Raster (pixel) text mode KDSBORDER int *color Set the border color of the current (virtual) console. KDRASTER scr_size_t *sizes Set raster (pixel) text mode and adjust the current (virtual) console's geometry and font size. The scr_size_t argument structure is as follows: struct _scr_size { int scr_size[3]; }; GIO_SCRNMAP scrmap_t *map PIO_SCRNMAP scrmap_t *map Get or set the screen map for the current (virtual) console. The scrmap_t argument structure is defined as follows: struct _scrmap { char scrmap[256]; }; GIO_ATTR int *attr Get the current text attribute. GIO_COLOR int *color Get the current text color. CONS_CURRENT int *type Get the adapter type. This is equivalent to FBIO_ADPTYPE. CONS_GET int *mode Get the current video mode. This is equivalent to FBIO_GETMODE. CONS_SET int *mode Set the current video mode. This is equivalent to FBIO_SETMODE. CONS_BLANKTIME int *time Set the screen saver blank interval (in seconds). CONS_CURSORTYPE int *type Set the text cursor shape. The argument type can be one or more of the following: CONS_BLINK_CURSOR Set for a blinking cursor, unset for a non- blinking cursor. CONS_CHAR_CURSOR Set for an underscore-shaped cursor, unset for a rectangle. CONS_BELLTYPE int *type Set the bell type. The argument type is one or more of: CONS_VISUAL_BELL Set for a visual bell, unset for an audible bell. CONS_QUIET_BELL Set to enable the bell, unset to disable it. CONS_HISTORY int *size Set the history (scroll back) buffer size (in lines). CONS_CLRHIST Clear the history (scroll back) buffer. CONS_IDLE int *idle Check if the (virtual) console has been idle. CONS_SAVERMODE int *mode Set the screen saver mode. The argument mode can be one of: CONS_NO_SAVER Disable screen saver CONS_USR_SAVER Enable screen saver CONS_LKM_SAVER Add a new screen saver CONS_SAVERSTART int *start Start or stop the screen saver. PIO_FONT8x8 fnt8_t *font GIO_FONT8x8 fnt8_t *font Get or set the 8x8 font. The fnt8_t argument structure is defined as follows: struct fnt8 { char fnt8x8[8*256]; }; PIO_FONT8x14 fnt14_t *font GIO_FONT8x14 fnt14_t *font Get or set the 8x14 font. The fnt14_t argument structure is defined as follows: struct fnt14 { char fnt8x14[14*256]; }; PIO_FONT8x16 fnt16_t *font GIO_FONT8x16 fnt16_t *font Get or set the 8x16 font. The fnt16_t argument structure is defined as follows: struct fnt16 { char fnt8x16[16*256]; }; CONS_GETINFO vid_info_t *info Get information about the current video mode. The vid_info_t structure is defined as follows: struct vid_info { short size; short m_num; u_short font_size; u_short mv_row, mv_col; u_short mv_rsz, mv_csz; struct colors mv_norm, mv_rev, mv_grfc; u_char mv_ovscan; u_char mk_keylock; }; CONS_GETVERS int *version Get the version of the driver. CONS_CURRENTADP int *adapter Get the video adapter index. This is equivalent to FBIO_ADAPTER. CONS_ADPINFO video_adapter_info_t *info Get the video adapter information. This is equivalent to FBIO_ADPINFO. CONS_MODEINFO video_info_t *info Get the video mode information. This is equivalent to FBIO_MODEINFO. CONS_FINDMODE video_info_t *info Find a video mode. This is equivalent to FBIO_FINDMODE. CONS_SETWINORG u_int *origin Set the frame buffer window origin. This is equivalent to FBIO_SETWINORG. CONS_SETKBD int *kbd Set a new keyboard. CONS_RELKBD Release the current keyboard. CONS_SCRSHOT scrshot_t *data Make a snapshot of the current video buffer. The scrshot_t structure is defined as: struct scrshot { int xsize; int ysize; u_int16_t* buf; }; CONS_GETTERM term_info_t *info CONS_SETTERM term_info_t *info Get or set terminal characteristics. The term_info_t structure is defined as: struct term_info { int ti_index; int ti_flags; u_char ti_name[TI_NAME_LEN]; u_char ti_desc[TI_DESC_LEN]; }; VT_OPENQRY int *term Get the next available terminal. VT_SETMODE vtmode_t *mode VT_GETMODE vtmode_t *mode Get or set the terminal switching mode. The vtmode_t argument structure is defined as follows: struct vt_mode { char mode; char waitv; short relsig; short acqsig; short frsig; }; VT_RELDISP int *ack Acknowledge the release or acquisition of a terminal. The ack argument can be one of: VT_FALSE The user refuses to release the screen, abort VT_TRUE The user has released the screen, go on VT_ACKACQ Acquisition of the screen acknowledged, switch completed VT_ACTIVATE int *term Activate the specified terminal. VT_WAITACTIVE int *term Wait until the specified terminal is active. VT_GETACTIVE int *term Get the currently active terminal. VT_GETINDEX int *index Get the index of the terminal. VT_LOCKSWITCH int *lock Prevent or permit terminal switching.


/dev/console /dev/consolectl /dev/ttyv? virtual terminals /etc/ttys terminal initialization information /usr/share/syscons/fonts/* font files /usr/share/syscons/keymaps/* key map files /usr/share/syscons/scrmaps/* screen map files


As the syscons driver requires the keyboard driver and the video card driver, the kernel configuration file should contain the following lines. device atkbdc0 at isa? port IO_KBD device atkbd0 at atkbdc? irq 1 device vga0 at isa? device sc0 at isa? pseudo-device splash If you do not intend to load the splash image or use the screen saver, the last line is not necessary, and can be omitted. Note that the keyboard controller driver atkbdc is required by the keyboard driver atkbd. The following lines will set the default colors. The normal text will be green on black background. The reversed text will be yellow on green background. Note that you cannot put any white space inside the quoted string, because of the current implementation of config(8). options SC_NORM_ATTR=(FG_GREEN|BG_BLACK) options SC_NORM_REV_ATTR=(FG_YELLOW|BG_GREEN) The following lines will set the default colors of the kernel message. The kernel message will be printed bright red on black background. The reversed message will be black on red background. options SC_KERNEL_CONS_ATTR=(FG_LIGHTRED|BG_BLACK) options SC_KERNEL_CONS_REV_ATTR=(FG_BLACK|BG_RED) The following line will set the default border color of the terminal. If the console is in framebuffer mode, or in raster (pixel) text mode, a thin green border will be visible around the terminal if the screen size is not an exact multiple of the font size. This border area can be much larger if the column or row count is explicitly specified (for example when using the kern.kms_columns tunable). options SC_BORDER_COLOR=FG_GREEN The following example adds the font files cp850-8x16.fnt, cp850-8x14.font and cp850-8x8.font to the kernel. options SC_DFLT_FONT makeoptions SC_DFLT_FONT=cp850 device sc0 at isa?


The amount of data that is possible to insert from the cut buffer is limited by the {MAX_INPUT}, a system limit on the number of bytes that may be stored in the terminal input queue - usually 1024 bytes (see termios(4)).


kbdcontrol(1), login(1), vidcontrol(1), atkbd(4), atkbdc(4), keyboard(4), screen(4), splash(4), sysmouse(4), ukbd(4), vga(4), kbdmap(5), rc.conf(5), ttys(5), getty(8), kldload(8), moused(8)


The syscons driver first appeared in FreeBSD 1.0.


The syscons driver was written by Soren Schmidt <sos@FreeBSD.org>. This manual page was written by Kazutaka Yokota <yokota@FreeBSD.org> and Sascha Wildner.


This manual page is incomplete and needs revision. DragonFly 6.3-DEVELOPMENT June 18, 2022 DragonFly 6.3-DEVELOPMENT

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