1.\" $NetBSD: wsdisplay.4,v 1.8 2001/06/10 15:43:56 wiz 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 options WSDISPLAY_DEFAULTSCREENS=N 26.Sh DESCRIPTION 27The 28.Nm 29driver is an abstraction layer for display devices within the 30.Xr wscons 4 31framework. It attaches to the hardware specific display device 32driver and and makes it available as text terminal or graphics 33interface. 34.Pp 35A display device can have the ability to display characters on it 36(without help of an X server), either directly by hardware or through 37software putting pixel data into the display memory. 38Such displays are called 39.Dq emulating , 40the 41.Nm 42driver will connect a terminal emulation module and provide a 43tty-like software interface. In contrary, non-emulating displays can only 44be used by special programs like X servers. 45.Pp 46The 47.Em console 48locator in the configuration line refers to the device's use as output 49part of the operating system console. A device specification containing 50a positive value here will only match if the device is in use as system 51console. (The console device selection in early system startup is not 52influenced.) This way, the console device can be connected to a known 53wsdisplay device instance. (Naturally, only 54.Dq emulating 55display devices are usable as console.) 56.Pp 57The logical unit of an independent contents displayed on a display 58(sometimes referred to as 59.Dq virtual terminal 60) is called a 61.Dq screen 62here. If the underlying device driver supports it, multiple screens can 63be used on one display. (As of this writing, only the 64.Xr vga 4 65and the 66.Tn VAX 67.Dq smg 68display drivers provide this ability.) 69Screens have different minor device numbers and separate tty instances. 70One screen possesses the 71.Dq focus , 72this means it is displayed on the display and its tty device will get 73the keyboard input. (In some cases - if no screen is set up or if a screen 74was just deleted - it is possible that no focus is present at all.) 75The focus can be switched by either special keyboard input (typically 76CTRL-ALT-Fn) or an ioctl command issued by a user program. 77Screens are set up or deleted through the 78.Pa /dev/ttyEcfg 79control device (preferably using the 80.Xr wsconscfg 8 81utility). Alternatively, the compile-time option 82.Cd WSDISPLAY_DEFAULTSCREENS=N 83will set up N screens of the display driver's default type and using 84the system's default terminal emulator at autoconfiguration time. 85.Sh FILES 86.Bl -item 87.It 88.Pa /dev/ttyE* 89Terminal devices (per screen). 90.It 91.Pa /dev/ttyEcfg 92Control device. 93.It 94.Pa /usr/include/dev/wscons/wsconsio.h 95.El 96.Sh BUGS 97The 98.Nm 99code currently limits the number of screens on one display to 8. 100.Pp 101The terms 102.Dq wscons 103and 104.Dq wsdisplay 105are not cleanly distinguished in the code and in manual pages. 106.Pp 107.Dq non-emulating 108display devices are not tested. 109.Sh SEE ALSO 110.Xr ega 4 , 111.Xr pcdisplay 4 , 112.Xr tty 4 , 113.Xr vga 4 , 114.Xr wscons 4 , 115.Xr wsconscfg 8 , 116.Xr wsconsctl 8 , 117.Xr wsfontload 8 118