On Thu, Feb 13, 2020 at 12:40:59PM -0500, Sadanand Warrier wrote: > Hi > I had question about PCIe hotplug. We have hardware that is connected > to the host by means of two PCIe switches. i.e. the host sees a PCIe switch > connected to one of its buses and on the far side of that switch another > PCIe switch which has a PCIe device. > It is possible that this device does not train its host facing PCIe > links before the server enumerates down its PCI bus and reaches those > links. It is also possible the PCIe switch to which the device is attached > has not been able to train its own links before server enumeration. > Is PCIe hotplug built to work on schemes like this? Let us assume that > the hardware has been designed to trasmit a presence signal once the links > are trained but this could happen after the server enumeration? Look at the PCIe hotplug spec, it should answer all of your questions about this. > Incidentally does the server take advantage of the BIOS/UEFI enumeration? Yes, of course, how else would the kernel be able to enumerate PCI devices? :) thanks, greg k-h _______________________________________________ Kernelnewbies mailing list Kernelnewbies@xxxxxxxxxxxxxxxxx https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
