I'm trying to make vga* at pci? attach the onboard Mach64 GT VGA of my Ultra5.

I found the framebuffer is not at the usual (aka PC-ish) location. On a PC
the VGA card has all BARs completely zero (i.e. unimplemented). On the sun
the BAR at 0x10 points to the framebuffer and the BAR at 0x14 to the IO
region of the VGA.

I do not have access to the PCI spec (is that publicaly available?), and I do
not dare to change such a widely used device as sys/dev/pci/vga_pci.c and 
sys/dev/ic/vga.c without some confirmation that I'm doing the right thing.

Is a "VGA Display" class device supposed to either default to the typical
PC addresses or have the BARs mentioned above point to the right thing?

If I check for valid BAR 0x10 and then do the sparc-ish thing, will this
likely break any PC VGA card?


Martin