VGA arbitration: API proposal

[Jon Smirl]

Does it make sense to work towards the goal of eliminating VGA use (if
hardware allows) except for early boot and system recovery?

For example, current ATI/Nvidia/Intel hardware can completely disable
VGA. But most x86 users boot with these cards using VGAcon. Could we
fix things so that fbcon would automatically be used for these cards
instead of VGAcon?

I might even take this one step further and eliminate VGAcon as
something that loads automatically. Instead I would require every
video card to load a fbdev driver. One fbdev driver would be for VGA
devices. It would support a single instance only. This fbdev VGA
driver could probably work with fbcon, allowing VGAcon to be
eliminated.

The new model would be something like this:
1) all video cards need a driver
2) one fbdev driver is a generic VGA one, it is exclusive
3) cards that can work without VGA have their own drivers
4) everyone shares fbcon
5) VGAcon is still around but if loaded fbdev drivers will refuse to
load, force VGAcon use at boot time with kernel parameter vgacon=yes.

Driver #2 implements Ben's locking scheme.
Driver #2 can shut down long enough to post type #3 cards
If a Driver #3 has to use VGA ports (hopefully none do) the locking is in-place
Jesse can relax the exclusive rule on IA64 to one per bus

-- 
Jon Smirl
jonsmirl at gmail.com