For VGA ...

[ron minnich]

VGA is "special".

This code: 
src/devices/device.c:static void allocate_vga_resource(void)

is great.

This loop:
         while(bus) {
                bus->bridge_ctrl |= PCI_BRIDGE_CTL_VGA;
                bus = (bus == bus->dev->bus)? 0 : bus->dev->bus;
        }

is close, but as noted it is somewhat pci-centric. It works darned well 
though: it sets up most bridges just fine.

But VGA is just so darned "SPECIAL".

I am thinking of adding a new device_operation just for good old vga.

void (*endable_vga)(dev, vga_dev)

The loop changes to this:

while(bus) {
    	if (bus->dev->ops && bus->dev->ops->enable_vga)
    		bus->dev->ops->enable_vga(bus->dev, vga);
    	else
                    bus->bridge_ctrl |= PCI_BRIDGE_CTL_VGA;
                bus = (bus == bus->dev->bus)? 0 : bus->dev->bus;
        }

I think this is all we need. Most of the devices would have this empty, 
but the amdk8 would have an entry so it could: 
- set the VGA_EN bit in the correct PCI I/O register
- set up an MMIO pair for the a0000-affff range

I realize this is a special case, but all of vga is a special case, and 
VGA is *very* *important* to the embedded space. Our goal is to have a VGA 
filo or etherboot prompt.

comments? Absent serious objections I want to put this in today.

ron