On 06/15/2015 09:50 AM, Gerd Hoffmann wrote:
Hi,
I'm wondering whenever things become easier if we add config registers to the pxb, where the firmware can program the bus number range and we can use the config register base as a way to specify which pxb we are referring to ?
... and, while thinking about ben's reply elsewhere in this thread, maybe even decouple the whole thing from the primary root bus? You can't program the devices via 0x0cf8 then, but we could add a mmconfig bar to the host bridge device ...
Hi Gerd,
I thought about it of course, but it seemed to me to be over-kill and no real reason to do it. I would hove done it if: - there would be a "generic" spec for such a host-bridge specifying at least the registers for the bus number. I didn't find anything => => Seabios should be aware of a special QEMU device and look for it... ugly - I would have seen how Seabios/coreboot program the above bus number. Again, didn't find the host-bridge programming code. At last, I followed a 'real' PXB device, some old Intel snooping host bridge.
As always, I am open to ideas, but, the latest patches from Laszlo follows Seabios way, and if OVMF can also handle it maybe we can stop: "The use of logical bus number instead of bus index" discussion and start arguing on something else. :)
I just want to say thank you to everybody involved, a lot of information and good guidelines surfaced during this talk.
Until the next patch... Thanks, Marcel
cheers, Gerd