Supporting extension ROMs and beyond...

Steve Gehlbach steve at
Mon Aug 11 13:29:00 CEST 2003

> Eric, I am sympathy with what you are saying. There is a reality here -- 
> people want VGA and they want it on early. I want to accomodate this. 
> ron

There is always the direct register programming approach that we have 
for the sis630 and stpc, but in the case of the sis630, vga is not 
available immediately due to the PCI init not done yet.  Right after PCI 
init, it comes on.  I suspect this just a few bits in some bridge 
registers, but I have not cared enough to go look.  The stpc is immediate.

Most if not all of the chips and cards support the legacy registers for 
text mode.  But there are always a few magic registers that need to be 
setup to enable legacy mode, and when you don't have the docs, it means 
reverse engineering the BIOS.

I do this quite a bit with the IDA disassembler (comm'l product on 
Windows from datarescue), and it is not so difficult, but very time 
consuming.  And right now I am very busy.

So in the end the most expedient way to get VGA is with the BIOS calls 
and a binary.

I will someday get to more work on VGA disassembly, it is a hobby, some 
people play chess, I disassemble BIOSes.

So how many requests do you get for direct booting vmlinuz.gz from IDE 
(linux fs compatible ala grub or lilo)?


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