Difference between revisions of "Generic VESA video driver"

Latest revision as of 12:40, 1 March 2014

VESA (Video Electronics Standards Association) as it relates to video display on a computer monitor, video card adapter, and display resolutions, produces a universal standard for computer graphics founded in 1989 by NEC Home Electronics and eight other video display adapter manufacturers.

The first VESA standard was for 800×600 SVGA resolution video displays.

The VESA Software Standards Committee was closed down due to a lack of interest resulting from charging high prices for specifications.[2] At that time no VESA standards were available for free. Although VESA now hosts some free standards documents, the free collection does not include newly developed standards. Even for obsolete standards, the free collection is incomplete.

Discussion of VESA complete standards and the organization is beyond the scope of this document.

In Microsoft Windows 95 the default "compatibility" display resolution was 640x480 using VESA standards. Later in Windows 98 the new lowest default was 800x600 using VESA standards. These "safe mode" display resolutions were a fallback if no video driver specific for the system video adapter was installed. These are the best known VESA display standards. See also Legacy PC Display Standards.

VESA video driver for Microsoft Windows

In Windows NT, Windows 2000, Windows XP or Windows Server 2003 display properties:

• Select Display Adapters from the Select Hardware Type dialog box.
• Select Standard Display Adapter (VGA) from the device list, then click OK.

The video supports vesa many modes.

Mode 011dh    320 x 200    APA        256 colors
Mode 010eh    320 x 200    APA      65536 colors
Mode 0100h    640 x 400    APA        256 colors
Mode 0127h    640 x 400    APA      65536 colors
Mode 0128h    640 x 400    APA   16777216 colors
Mode 0101h    640 x 480    APA        256 colors
Mode 0110h    640 x 480    APA      32768 colors
Mode 0111h    640 x 480    APA      65536 colors
Mode 0112h    640 x 480    APA   16777216 colors
Mode 0102h    800 x 600    APA         16 colors
Mode 0103h    800 x 600    APA        256 colors
Mode 0113h    800 x 600    APA      32768 colors
Mode 0114h    800 x 600    APA      65536 colors
Mode 0115h    800 x 600    APA   16777216 colors
Mode 0105h   1024 x 768    APA        256 colors

VESA video driver for Linux

vesa is an Xorg driver for generic VESA video cards. It can drive most VESA-compatible video cards, but only makes use of the basic standard VESA core that is common to these cards. The driver supports depths 8, 15 16 and 24.

The default graphics driver is vesa (package xf86-video-vesa), which handles a large number of chipsets but does not include any 2D or 3D acceleration. If a better driver cannot be found or fails to load, Xorg will fall back to vesa.

Here is an example for a GRUB stanza, I grabbed out of my /boot/grub/menu.lst":

title           Debian GNU/Linux, kernel 2.6.18-4-k7
root            (hd0,0)
kernel          /vmlinuz-2.6.18-4-k7 root=/dev/hde2 ro vga=791 
initrd          /initrd.img-2.6.18-4-k7

You could also have it look like this:

title           Debian GNU/Linux, kernel 2.6.18-4-k7
root            (hd0,0)
kernel          /vmlinuz-2.6.18-4-k7 root=/dev/hde2 ro vga=0x317 
initrd          /initrd.img-2.6.18-4-k7

VESA video modes in MSDOS

MS-DOS VESA mode selection was well known to PC gamers back in the early 1990's. Most PC games of the day ran in DOS mode. These games largely did not support the vast array of proprietary video drivers available with some exceptions. The VESA mode drivers allowed gamers to display the best possible resolution and color depth for a wide array of video cards. Game developers were able to simply video card support by using VESA standards.

Color depth of up to 24-bit are possible using DOS Super VGA VESA standard modes in MS-DOS. Most of the modern videocards comes with a VBE2-Bios or a VBE3-Bios and with an own modetable of vbe modenumbers maybe with a resolutions up to 2048x1536 pixel and with 8, 15 or 16, 24 or 32 bits per pixel and with a aspect ratio of 4:3, 4:5, 16:9 and 16x10.

SuperVGA programming uses screen data that can exceed 1 MB in size. However, the normal VGA card only offers a 64k memory access at A000h (some cards provide 128k).