>From the webpage and the mailing list, it seems that Linuxbios has
graphics support only for the embedded chip in SiS-based motherboards,
and then it is supported by the fb driver of linux, which means you
have to load a linux kernel to get text on your monitor (that is,
unless your monitor is a terminal plugged on your serial port...). Am
I right?
Is there any code *in* linuxbios to set up a VGA adapter (either in
'hardare' text mode, or in graphics mode)? Or perhaps I should be
looking for it in some other project like TIARA?
It seems that the linuxbios philosophy is ''if the kernel can do it,
then let the kernel do it''. Yet, for cases where a linux kernel
won't fit in the FLASH, it would be nice to have something like a list
of choices on your video.
And now some more 'technical' questions:
Does Linux use the VGA BIOS in any way? (IIRC it is used by vesafb,
but are there any other cases?). Of course it relies on the VGA BIOS
(or someone else) to have set up the card for text mode, but does it
actually use INT10? Does it use any of the data present in the VGA
BIOS (the whole BIOS is there, I can see it in /dev/mem, but is it
ever read?). What I am getting to is: if I can set up my VGA card in
80x25 text mode (or any other text mode) from linuxbios, will Linux
run happily? (And then, will X run happily? will switching from X to
text mode and back again work?)
Do I have to setup the card in any way before I can access it's I/O
ports from the CPU? (Actually I'm curious about the general question:
how do the expansion cards 'register' their I/O ports? And what
happens if I install two cards that would use the same ports (e.g. two
VGA cards)? How do I access each of them?. I'm thinking about PCI
cards, but I'm also curious about other types, like ISA)
The VGA BIOS is present at 0C000h:0000 (or 0x000C0000, whichever you
like). Is it mapped there automagically (like the PC BIOS is), or the
PC BIOS maps it there? How do I switch between address 0x000C0000
referencing the VGA ROM and the RAM memory (which usually contains a
copy of the VGA BIOS, but in linuxbios it doesn't (does it?), and it
would be useful to load stuff like the text mode fonts from the VGA
ROM)?
Thanks for any reply to my (admittedly TOO many) questions,
Stefanoss
