VGA arbitration: API proposal

[Egbert Eich]

Jon Smirl writes:
 > There is no real reason to be using VGA in current machines. Could we
 > take this concept further and separate all cards into two piles:
 > require VGA or can live without it. The obvious exception to this is
 > during the post process.

This doesn't take you all the way. After posting we can expect that
almost all cards have VGA enabled. Certainly during POSTing a lot
of cards require VGA as MMIO space is not accessible in the mode
the CPU is in at POST time. 
Some cards do interesting tricks (by mapping legacy registers into
PCI config space).

 > So my simple idea is:
 > mark all drivers as VGA or not
 > only allow a single card in the system that is marked as requiring VGA
 > require fbdev/fbcon on the non-VGA cards
 > the first card that arrives requiring VGA get VGAcon
 > build whatever is needed to get through the post process for non-VGA cards
 > if there is a second VGA required card, print a big message and refuse to boot
 > discourage any further writing of code that uses VGA

I don't think this will work in reality.

Cheers,
	Egbert.