On Thu, Oct 03, 2013 at 06:08:15PM -0700, Rajat Jain wrote: > Hello, > > On Sun, Sep 29, 2013 at 7:05 PM, Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx> wrote: > > On Sun, Sep 29, 2013 at 11:27:23AM -0700, Rajat Jain wrote: > >> Hello List, > >> > >> Today all the PCI Hot-plug drivers (shpc, acpihp, cpqhp, ibmhp etc > >> except pciedhp) directly claim the downstream port bridge device. > >> Where as in case of pciehp, the PCIe port bus driver claims the bridge > >> device, and service drivers (aer, pm, pciehp) simply register for the > >> service with it. > >> > >> 1) Does that mean that in a system where I am using a driver other > >> than pciehp for hot-plug (eg. shpc), I cannot use service drivers like > >> AER or PM on the same port (since the device would be claimed by > >> shpc, it would not be available to port bus driver)? > > > > It depends on your system, and you BIOS, which sets up all of this > > stuff. It's up to the kernel to bind to the proper things it exposes. > > Actually, I just wanted to understand that on a machine where > shpchp.ko is to be used for hot-plug, can I still use the AER port bus > service driver? My understanding is NO, because shpc will claim the > downstream port bridge, and hence port bus driver will not be able to > claim it? I think you are correct, at least in principle. Both pcie_portdriver and shpc_driver try to claim all PCI bridge devices. pcie_portdrv_probe() succeeds only for PCIe Root Ports, Upstream Ports, and Downstream Ports. shpc_probe() succeeds only for bridges with the SHPC capability. If one of them does claim the bridge, the driver core should not call the other probe method. So if you have a PCIe Root Port or switch port that has the SHPC capability, either pcie_portdrv_probe() or shpc_probe() will fail, depending on which was called first. I've never seen such a device, so I don't know whether this is a problem in practice. Bjorn -- To unsubscribe from this list: send the line "unsubscribe linux-hotplug" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
