Dear Jason Gunthorpe, On Thu, 20 Feb 2014 17:32:27 -0700, Jason Gunthorpe wrote: > > In practice, the story is a little bit more subtle than that: the PCIe > > driver may want to decide to either tell the PCI core to enlarge the > > window BAR up to the next power of two size, or to dedicate two windows > > to it. > > That is a smart, easy solution! Maybe that is the least invasive way > to proceed for now? So you suggest that the mvebu-mbus driver should accept a non power-of-two window size, and do internally the job of cutting that into several power-of-two sized areas and creating the corresponding windows? > I have no idea how you decide when to round up and when to allocate > more windows, that feels like a fairly complex optimization problem! Yes, it is a fairly complex problem. I was thinking of a threshold of "lost space". Below this threshold, it's better to enlarge the window, above the threshold it's better to create two windows. But not easy. > Alternatively, I suspect you can use the PCI quirk mechanism to alter > the resource sizing on a bridge? Can you give more details about this mechanism, and how it could be used to alter the size of resources on a bridge? > > Jason, would you mind maybe replying to Bjorn Helgaas email (Thu, 20 > > Feb 2014 12:18:42 -0700) ? I believe that a lot of the misunderstanding > > between Bjorn and me is due to the fact that I don't use the correct > > PCI terminology to describe how the Marvell hardware works, and how the > > Marvell PCIe driver copes with it. I'm sure you would explain it in a > > way that would be more easily understood by someone very familiar with > > the PCI terminology such as Bjorn. Thanks a lot! > > Done! Thanks a lot! Really appreciated. Best regards, Thomas -- Thomas Petazzoni, CTO, Free Electrons Embedded Linux, Kernel and Android engineering http://free-electrons.com -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
