Early console attach vs PCI_NETBSD_CONFIGURE

[Gavan Fantom <gavan%coolfactor.org@localhost>]

Hi folks,

I'm trying to find a good way to do early console attach on 
NetBSD/iyonix with a genfb-based console.

The graphics card is a NVidia GeForce2 MX which is supplied with the 
machine, and there are drivers in flash for RISC OS, which boots 
natively on the machine.

NetBSD reconfigures the PCI bus early on during boot, so the base 
addresses of the devices can and do move around from the way RISC OS 
chose to lay out the bus.

The NetBSD bootloader passes enough information through about how RISC 
OS has configured the card that we can attach genfb to it.

I'd like to attach the console early so that we can get early boot 
messages appearing on the screen, but the problem is that if I do that 
then the base address of the graphics card will move during 
autoconfiguration and genfb will be left writing kernel messages to 
memory which may not be backed by an actual framebuffer.

I can't see an obvious hook where I can reattach genfb with the new 
address, and setup_memwins (in pci/pciconf.c) is peppered with calls to 
printf guarded by pci_conf_debug. Given that after changing the base 
address of the framebuffer and before reattaching the console a printf 
could be fatal, I don't think simply reattaching after pciconf has done 
its thing is enough.

I'm reluctant to add a hook that will be called immediately after 
changing every single base address register, but that's the only way I 
can think of right now.

Is there a better way to do this?

--
Gilette - the best a man can forget