Timothy Miller wrote:
Certainly, I think we should implement 1.x first, but we should examine 2.x to make sure we don't leave out any important hardware features.
VBE 2.0 is the important standard -- VBE 1.x support alone would not be very useful. The big difference between 2.0 and the preceding 1.2 was the introduction of LFB support (Linear Frame Buffer) where a protected mode application (games using a DOS extender such as DOS4/GW, mostly) could map the entire framebuffer in a standardised way through VBE calls and this capability was important back then so the standard stuck.
The current VBE version is 3.0:
http://www.vesa.org/public/VBE/vbe3.pdf
but I've never seen anyone care about any version higher than 2.0 either. In modern Linux, I know of three uses of the VESA BIOS extensions:
1) The vesafb framebuffer
This needs VBE 2.0
2) MPlayer's "-vo vesa" output driver
Also VBE 2.0
3) X's use of DDC to get the EDID information
At least on my hardware (ATI Rage128) X uses VBE/DDC to query the monitor:
(II) R128(0): VESA BIOS detected (II) R128(0): VESA VBE Version 2.0 (II) R128(0): VESA VBE Total Mem: 16384 kB (II) R128(0): VESA VBE OEM: ATI RAGE128 (II) R128(0): VESA VBE OEM Software Rev: 1.0 (II) R128(0): VESA VBE OEM Vendor: ATI Technologies Inc. (II) R128(0): VESA VBE OEM Product: R128 (II) R128(0): VESA VBE OEM Product Rev: 01.00 (II) Loading sub module "ddc" (II) LoadModule: "ddc" (II) Reloading /usr/X11R6/lib/modules/libddc.a (II) R128(0): VESA VBE DDC supported (II) R128(0): VESA VBE DDC Level 2 (II) R128(0): VESA VBE DDC transfer in appr. 2 sec. (II) R128(0): VESA VBE DDC read successfully
VBE/DCC is a supplemental standard:
http://www.vesa.org/public/VBE/VBEDDC11.PDF
and seems independent of the VBE core version.
Now, for all three, usefulness can be questioned:
1) Who needs vesafb when we have ogpfb?
2) Who needs "-vo vesa" when we have "-vo ogp"?
3) Why bother with VBE/DCC when the OGP driver could provide the EDID info "natively"?
As to 3, I don't suppose X would object to not going through VBE/DDC but Windows might be an argument -- I have no idea what it requires.
Rene. _______________________________________________ Open-graphics mailing list [email protected] http://lists.duskglow.com/mailman/listinfo/open-graphics List service provided by Duskglow Consulting, LLC (www.duskglow.com)
