1.\" $NetBSD: wsdisplay.4,v 1.11 2001/11/29 23:19:52 ross Exp $ 2.Dd March 20, 1999 3.Os 4.Dt WSDISPLAY 4 5.Sh NAME 6.Nm wsdisplay 7.Nd generic display device support in wscons 8.Sh SYNOPSIS 9.Cd wsdisplay* at ega? console ? 10(EGA display on ISA) 11.Cd wsdisplay* at vga? console ? 12(VGA display on ISA or PCI) 13.Cd wsdisplay* at pcdisplay? console ? 14(generic PC (ISA) display) 15.Cd wsdisplay* at tga? console ? 16(DEC TGA display, alpha only) 17.Cd wsdisplay* at pfb? console ? 18(PCI framebuffer, bebox only) 19.Cd wsdisplay0 at ofb? console ? 20(Open Firmware framebuffer, macppc only) 21.Cd wsdisplay* at nextdisplay? console ? 22(NeXT display) 23.Cd wsdisplay0 at smg0 24(VAXstation small monochrome display) 25.Cd wsdisplay* at ... kbdmux N 26.Cd options WSDISPLAY_DEFAULTSCREENS=N 27.Sh DESCRIPTION 28The 29.Nm 30driver is an abstraction layer for display devices within the 31.Xr wscons 4 32framework. It attaches to the hardware specific display device 33driver and and makes it available as text terminal or graphics 34interface. 35.Pp 36A display device can have the ability to display characters on it 37(without help of an X server), either directly by hardware or through 38software putting pixel data into the display memory. 39Such displays are called 40.Dq emulating , 41the 42.Nm 43driver will connect a terminal emulation module and provide a 44tty-like software interface. In contrary, non-emulating displays can only 45be used by special programs like X servers. 46.Pp 47The 48.Em console 49locator in the configuration line refers to the device's use as output 50part of the operating system console. A device specification containing 51a positive value here will only match if the device is in use as system 52console. (The console device selection in early system startup is not 53influenced.) This way, the console device can be connected to a known 54wsdisplay device instance. (Naturally, only 55.Dq emulating 56display devices are usable as console.) 57.Pp 58The 59.Em kbdmux 60locator in the configuration line refers to the 61.Xr wsmux 4 62that will be used to get keyboard events. If this locator is -1 no 63mux will be used. 64.Pp 65The logical unit of an independent contents displayed on a display 66(sometimes referred to as 67.Dq virtual terminal 68) is called a 69.Dq screen 70here. If the underlying device driver supports it, multiple screens can 71be used on one display. (As of this writing, only the 72.Xr vga 4 73and the 74.Tn VAX 75.Dq smg 76display drivers provide this ability.) 77Screens have different minor device numbers and separate tty instances. 78One screen possesses the 79.Dq focus , 80this means it is visible and its tty device will get 81the keyboard input. (In some cases \- if no screen is set up or if a screen 82was just deleted \- it is possible that no focus is present at all.) 83The focus can be switched by either special keyboard input (typically 84.Tn CTRL-ALT-F Ns Ar n ) 85or an ioctl command issued by a user program. 86Screens are created and deleted through the 87.Pa /dev/ttyEcfg 88control device (preferably using the 89.Xr wsconscfg 8 90utility). Alternatively, the compile-time option 91.Dv WSDISPLAY_DEFAULTSCREENS Ns = Ns Ar n 92will also create (at autoconfiguration time) 93.Ar n 94initial screens of the display driver's default type with 95the system's default terminal emulator. 96.Sh FILES 97.Bl -item 98.It 99.Pa /dev/ttyE* 100Terminal devices (per screen). 101.It 102.Pa /dev/ttyEcfg 103Control device. 104.It 105.Pa /usr/include/dev/wscons/wsconsio.h 106.El 107.Sh SEE ALSO 108.Xr ega 4 , 109.Xr pcdisplay 4 , 110.Xr tty 4 , 111.Xr vga 4 , 112.Xr wscons 4 , 113.Xr wsconscfg 8 , 114.Xr wsconsctl 8 , 115.Xr wsfontload 8 116.Sh BUGS 117The 118.Nm 119code currently limits the number of screens on one display to 8. 120.Pp 121The terms 122.Dq wscons 123and 124.Dq wsdisplay 125are not cleanly distinguished in the code and in manual pages. 126.Pp 127.Dq non-emulating 128display devices are not tested. 129