1.\" $OpenBSD: wsdisplay.4,v 1.7 2001/06/23 07:04:01 pjanzen Exp $ 2.\" $NetBSD: wsdisplay.4,v 1.5 2000/05/13 15:22:19 mycroft Exp $ 3.\" 4.Dd March 20, 1999 5.Dt WSDISPLAY 4 6.Os 7.Sh NAME 8.Nm wsdisplay 9.Nd generic display device support in wscons 10.Sh SYNOPSIS 11.Cd wsdisplay* at ega? console ? 12(EGA display on ISA) 13.Cd wsdisplay* at vga? console ? 14(VGA display on ISA or PCI) 15.Cd wsdisplay* at pcdisplay? console ? 16(generic PC (ISA) display) 17.Cd wsdisplay* at tga? console ? 18(DEC TGA display, alpha only) 19.Cd wsdisplay* at nextdisplay? console ? 20(NeXT display) 21.Cd wsdisplay* at sti? console ? 22(HP CRX and Visualize series framebuffers) 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. 32It attaches to the hardware specific display device driver and 33makes it available as text terminal or graphics interface. 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 drawing 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. 44In contrary, non-emulating displays can only be used by special programs 45like 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. 51A device specification containing a positive value here will only match 52if the device is in use as system console. 53(The console device selection in early system startup is not influenced.) 54This way, the console device can be connected to a known 55.Xr wsdisplay 4 56device instance. 57(Naturally, only 58.Dq emulating 59display devices are usable as console.) 60.Pp 61The logical unit of an independent contents displayed on a display 62(sometimes referred to as 63.Dq virtual terminal 64) is called a 65.Dq screen 66here. 67If the underlying device driver supports it, multiple screens can 68be used on one display. 69(As of this writing, only the 70.Xr vga 4 71and the 72.Tn VAX 73.Dq smg 74display drivers provide this ability.) 75Screens have different minor device numbers and separate tty instances. 76One screen possesses the 77.Dq focus , 78this means it is displayed on the display and its tty device will get 79the keyboard input. 80(In some cases, if no screen is set up or if a screen 81was just deleted, it is possible that no focus is present at all.) 82The focus can be switched by either special keyboard input (typically 83CTL-ALT-Fn) or an ioctl command issued by a user program. 84Screens are set up or deleted through the 85.Pa /dev/ttyCcfg 86control decice (preferably using the 87.Xr wsconscfg 8 88utility). 89Alternatively, the compile-time option 90.Cm WSDISPLAY_DEFAULTSCREENS=N 91will set up N screens of the display driver's default type and using 92the system's default terminal emulator at autoconfiguration time. 93.Pp 94In addition and with help from backend drivers the following features 95are also provided: 96.Bl -bullet 97.It 98Loading, deleting and listing the loaded fonts. 99.It 100Browsing backwards in the screen output, the size of the 101buffer for saved text is defined by the particular hardware driver. 102.It 103Blanking the screen by timing out on inactivity in the 104screen holding the input focus. 105Awakening activities consist of: 106.Pp 107.Bl -bullet -compact 108.It 109pressing any keys on the keyboard; 110.It 111moving or clicking the mouse; 112.It 113any output to the screen. 114.El 115.Pp 116Blanking the screen is usually done by disabling the horizontal sync 117signal on video output, but may also include blanking the vertical 118sync in which case most monitors go into power saving mode. 119See 120.Xr wsconsctl 8 121for controlling variables. 122.El 123.Pp 124Consult the back-end drivers' documentation for which features are supported 125for each particular hardware type. 126.Sh FILES 127.Bl -tag -width /usr/include/dev/wscons/wsconsio.h -compact 128.It Pa /dev/ttyC* 129terminal devices (per screen) 130.It Pa /dev/ttyCcfg 131control device 132.It Pa /usr/include/dev/wscons/wsconsio.h 133.El 134.Sh SEE ALSO 135.Xr ega 4 , 136.Xr pcdisplay 4 , 137.Xr tty 4 , 138.Xr tga 4 , 139.Xr vga 4 , 140.Xr wscons 4 , 141.Xr wsconscfg 8 , 142.Xr wsconsctl 8 , 143.Xr wsfontload 8 144.Sh BUGS 145The 146.Nm 147code currently limits the number of screens on one display to 8. 148.Pp 149The terms 150.Dq wscons 151and 152.Dq wsdisplay 153are not cleanly distinguished in the code and in manual pages. 154.Pp 155.Dq non-emulating 156display devices are not tested. 157