This is the framebuffer device driver for the standard and
non-standard 256 color modes of the original VGA video card.
While the "tweaked" modes of the standard VGA don't provide
a linear framebuffer, vga256fb emulate it in software, wasting
your CPU and RAM but allowing a video mode up to 360x480 in 256 colors
with VGA cards without VESA BIOS extensions.
Since vga256fb doesn't use the BIOS at all you can compile
it as module, change the video mode at run-time, use tweaked
and standard modes in different consoles.
Supported modes are the following (all the modes are 256 colors):
The vga256fb comes with a 4x8 (uuhh!) font to provide an 80x25
console in 320x200, and a 90x60 console in 360x480.
As you can guess such font isn't so readable, however I developed
part of this framebuffer using this console without too problems.
- 320x200 (the old BIOS 13h chained mode)
- 256x256 (chained ModeQ)
- 320x240 (ModeX) (linear emulation)
- 400x300 (linear emulation)
- 360x480 (linear emulation)
- You can build a VGA based embedded system in 320x200x256 mode (the original goal of this driver)
- You can use a 256 color framebuffer as replacement for vga16fb, and see a good 256 colors logo (!)
- 320x200x256 can be useful for full-screen video.
- You can create a graphic enabled one-floppy linux distribution or installation software that will run almost everywhere with a decent 360x480x256 video mode.
Fortunatelly the driver will allocate the memory and waste the
CPU time only if you switch to a mode that requires linear emulation.
- The linear emulation will waste CPU time and memory.
- The 4x8 font is hard to read.
- Hey guys, we are in the 2001!
This software is under the GPL license
current version is 12-may-2001
get here the patch for Linux 2.4.4
get here the vga256ctrl utility to tune vga256fb (optional)
Linux Frame Buffer Driver Developers
Sat May 12 12:33:57 CEST 2001