> From: Jason Wang <[email protected]> > Sent: Wednesday, April 12, 2023 12:05 AM
> > > It is kind of intended since it is only used for new PCI-E features: > > > > > New fields in new extended pci cap area is fine. > > Migrating old fields to be present in the new extended pci cap, is not your > intention. Right? > > Right, but what I want to say is, such migration may cause unnecessary > problems. And I don't see why it is a must for your legacy MMIO bar proposal. > As I explained in the commit log, there is very small space left in the PCI capabilities. Last time I counted, our VF doesn’t even have space in the PCI cap 192 bytes anymore. So starting with the extended PCI cap for legacy MMIO bar window. > > Only currently defined caps to be placed in two places. > > What's the advantage of doing this? > I think Michael found one advantage of being 2x faster? > New drivers should provide backward compatibility so they must scan the pci > cap. Yes. > The Old driver can only scan the pci cap. > Yes. > > New fields don’t need to be placed in PCI cap, because no driver is looking > there. > > It would be much more simple if we forbid placing new fields in the PCI cap, > it is > already out of space. > Yes. We both are saying same point. :)
