1.\" $NetBSD: wsdisplay.4,v 1.5 2000/05/13 15:22:19 mycroft 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 vga? console ? 10(VGA display on ISA or PCI) 11.Cd wsdisplay* at pcdisplay? console ? 12(generic PC (ISA) display) 13.Cd wsdisplay* at tga? console ? 14(DEC TGA display, alpha only) 15.Cd wsdisplay* at pfb? console ? 16(PCI framebuffer, bebox only) 17.Cd wsdisplay0 at ofb? console ? 18(Open Firmware framebuffer, macppc only) 19.Cd wsdisplay* at nextdisplay? console ? 20(NeXT display) 21.Cd wsdisplay0 at smg0 22(VAXstation small monochrome display) 23.Cd options WSDISPLAY_DEFAULTSCREENS=N 24.Sh DESCRIPTION 25The 26.Nm 27driver is an abstraction layer for display devices within the 28.Xr wscons 4 29framework. It attaches to the hardware specific display device 30driver and and makes it available as text terminal or graphics 31interface. 32.Pp 33A display device can have the ability to display characters on it 34(without help of an X server), either directly by hardware or through 35software putting pixel data into the display memory. 36Such displays are called 37.Dq emulating , 38the 39.Nm 40driver will connect a terminal emulation module and provide a 41tty-like software interface. In contrary, non-emulating displays can only 42be used by special programs like X servers. 43.Pp 44The 45.Em console 46locator in the configuration line refers to the device's use as output 47part of the operating system console. A device specification containing 48a positive value here will only match if the device is in use as system 49console. (The console device selection in early system startup is not 50influenced.) This way, the console device can be connected to a known 51wsdisplay device instance. (Naturally, only 52.Dq emulating 53display devices are usable as console.) 54.Pp 55The logical unit of an independent contents displayed on a display 56(sometimes referred to as 57.Dq virtual terminal 58) is called a 59.Dq screen 60here. If the underlying device driver supports it, multiple screens can 61be used on one display. (As of this writing, only the 62.Xr vga 4 63and the 64.Tn VAX 65.Dq smg 66display drivers provide this ability.) 67Screens have different minor device numbers and separate tty instances. 68One screen posesses the 69.Dq focus , 70this means it is displayed on the display and its tty device will get 71the keyboard input. (In some cases - if no screen is set up or if a screen 72was just deleted - it is possible that no focus is present at all.) 73The focus can be switched by either special keyboard input (typically 74CTL-ALT-Fn) or an ioctl command issued by a user program. 75Screens are set up or deleted through the 76.Pa /dev/ttyEcfg 77control decice (preferrably using the 78.Xr wsconscfg 8 79utility). Alternatively, the compile-time option 80.Cd WSDISPLAY_DEFAULTSCREENS=N 81will set up N screens of the display driver's default type and using 82the system's default terminal emulator at autoconfiguration time. 83.Sh FILES 84.Bl -item 85.It 86.Pa /dev/ttyE* 87Terminal devices (per screen). 88.It 89.Pa /dev/ttyEcfg 90Control device. 91.It 92.Pa /usr/include/dev/wscons/wsconsio.h 93.El 94.Sh BUGS 95The 96.Nm 97code currently limits the number of screens on one display to 8. 98.Pp 99The terms 100.Dq wscons 101and 102.Dq wsdisplay 103are not cleanly distinguished in the code and in manual pages. 104.Pp 105.Dq non-emulating 106display devices are not tested. 107.Sh SEE ALSO 108.Xr wscons 4 , 109.Xr wsconscfg 8 , 110.Xr wsconsctl 8 , 111.Xr wsfontload 8 , 112.Xr vga 4 , 113.Xr pcdisplay 4 , 114.Xr tty 4 115