The video rom probe functions in arch/x86/kernel/probe_roms_32.c in the latest Linux kernel git tree is looking for a video rom with 0x55, 0xAA in the lowest two addresses.
Robert On Wed, Oct 08, 2008 at 07:56:20PM -0400, Timothy Normand Miller wrote: > During POST, the PC is supposed to assign addresses to OGD1's various > memory regions. It works fine for BAR0 and BAR1, but for some reason, > we end up with a zero in the EPROM BAR. In simulation, if we write an > address to the EPROM BAR, it works fine, so we need some ideas as to > why the host might be rejecting our EPROM. There are two things that > come to mind, but we don't see why they should matter. One is that we > show up as a VGA-compatible non-graphics device. This is probably a > mistake somewhere that we just haven't gotten around to fixing. The > second thing is that our EPROM contents do not start with AA55 (or > 55AA or whatever the signature is). Any other ideas? At some point, > we'll have to hook up a PCI bus analyzer and watch the boot process to > try to get some insight into this. Another idea is that since the > EPROM is blank, it's probably reading back all FF, which the host > might be interpreting as not being claimed by any device. One thing > that might help is if we had a dummy BIOS image (that it should think > of as valid but which doesn't DO anything) to program in there. > > Any ideas? > > -- > Timothy Normand Miller > http://www.cse.ohio-state.edu/~millerti > Open Graphics Project _______________________________________________ Open-graphics mailing list [email protected] http://lists.duskglow.com/mailman/listinfo/open-graphics List service provided by Duskglow Consulting, LLC (www.duskglow.com)
