Messages in this thread | | | Date | Mon, 20 Jul 1998 21:36:05 +0200 | From | Gerd Knorr <> | Subject | Re: vesa & v2.1.109 |
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In lists.linux.kernel you write:
>Hi guys,
>I've just realised that my graphic card is VESA 1.2 compliant and not VESA >2.0. Could this account for some people having problems using the vesafb >console? If that is so, it might be a nice idea to add an additional >vesafb module (say vesafb 1.2), and rename the vesafb to vesafb 2.0? This >might help to keep the legacy 1.2 graphic cards working with Linux's >vesafb.
No.
vesafb is very simple: The 16-bit bootcode switches to graphics mode and passes the parameters (framebuffer @ 0xff000000, 1024x768, 8bit color depth for example) to the vesafb driver. The hardware is _not touched_ later on (one exception: vga palette registers).
That's why VESA 2.0 is needed. We can't do bank-switching, and 1.2 does not support linear frame buffers. On the other hand: becauce the BIOS is not used any more once we switched to protected mode, you can use some DOS TSR which provides VESA 2.0 for your board (univbe?) and loadlin. I use this to run my board with reasonable refresh rates.
The big advantage of vesafb is that you don't need to know anything about the hardware to run the board in graphics mode and have X11 support for it.
On the other hand, there are a few drawbacks. No mode switches, no hardware acceleration. The GGI people (someone mentioned kgicon is already available in GGI-current) probably can do graphics alot better. Hardware acceleration for scrolling and other nice features...
Gerd
-- Gerd Knorr <kraxel@cs.tu-berlin.de>
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