Hi Bjorn, Lorenzo; On 8/25/2016 4:44 AM, Lorenzo Pieralisi wrote: > Hi Sinan, > > [+Alex] > > On Wed, Aug 24, 2016 at 03:28:51PM -0400, Sinan Kaya wrote: >> On 8/24/2016 3:10 PM, Bjorn Helgaas wrote: >>>> Where do we go from here? I was thinking of putting something deep down into the reset secondary >>>>> bus function but I'm afraid it will break things especially when we wait up to 60 seconds. >>> I agree CRS handling after reset is probably all broken. >>> >>> I hate the fact that we reset devices without re-enumerating them. We >>> have no assurance that the device is the same after reset (it could >>> have loaded new firmware and been completely reconfigured). >>> >>> I don't have any good suggestions for you, so if you have some ideas >>> and want to fix it, please go ahead. >> >> I think I'll make a list of paths that reach to secondary bus reset >> function and try to keep CRS loop as close as possible to the caller. >> >> I'll focus on FLR later. I won't be heart-broken if somebody took a >> stab at the FLR. > > Side note, taking advantage of this query: I hope this is a problem > solved by end of October, if it is not I would suggest adding a track to > tackle it at LPC16 PCI uconf, I added Alex since I know he is interested > in the topic too, it makes sense to debate a solution with all > interested people in one room. > Let's see where this goes. Here is a list of all the callers I found. Based on what I see, the code assumes that registers are accessible immediately after pci_reset_bridge_secondary_bus call. pci_reset_bridge_secondary_bus also sleeps for 1 seconds. We can maybe assume that it is OK to sleep additional potential 60 seconds. How do you feel about running CRS against all immediate children of this bridge in pci_reset_secondary_bus function by calling pci_bus_read_dev_vendor_id for every single child? Something like: + u32 l; + list_for_each_entry(dev, &bus->devices, bus_list) + pci_bus_read_dev_vendor_id(bus, dev->devfn, &l, 60*1000); trigger_sbr (infiniband/hw/hfi1/pcie.c) pci_reset_bridge_secondary_bus (export) pcibios_reset_secondary_bus (weak) pci_reset_secondary_bus __pci_reset_function pci_dev_reset __pci_dev_reset pci_dev_reset_slot_function pci_reset_hotplug_slot reset_slot (drivers/pci/hotplug/pciehp_core.c) pciehp_reset_slot (drivers/pci/hotplug/pciehp_hpc.c) pci_reset_bridge_secondary_bus (export) pcibios_reset_secondary_bus (weak) pci_reset_secondary_bus pcie_capability_write_word pci_parent_bus_reset pci_reset_bridge_secondary_bus pcibios_reset_secondary_bus (weak) pci_reset_secondary_bus pci_try_reset_function __pci_dev_reset pci_dev_restore pcistub_put_pci_dev __pci_reset_function_locked __pci_dev_reset pci_restore_state pcistub_init_device __pci_reset_function_locked __pci_dev_reset pci_restore_state handle_error_source do_recovery reset_link (drivers/pci/pcie/aer/aerdrv_core.c) default_reset_link pci_reset_bridge_secondary_bus (export) pcibios_reset_secondary_bus (weak) pci_reset_secondary_bus driver->reset_link aer_root_reset pci_reset_bridge_secondary_bus (export) pcibios_reset_secondary_bus (weak) pci_reset_secondary_bus pci_read_config_dword vfio_pci_ioctl (VFIO_DEVICE_PCI_HOT_RESET) pci_try_reset_bus pci_reset_bridge_secondary_bus pcibios_reset_secondary_bus (weak) pci_reset_secondary_bus vfio_pci_disable vfio_pci_try_bus_reset pci_try_reset_bus pci_reset_bridge_secondary_bus pcibios_reset_secondary_bus (weak) pci_reset_secondary_bus pci_probe_reset_bus (probe =1) pci_bus_reset pci_reset_bridge_secondary_bus pcibios_reset_secondary_bus (weak) pci_reset_secondary_bus vfio_pci_ioctl ( VFIO_DEVICE_GET_PCI_HOT_RESET_INFO) pci_probe_reset_bus (probe =1) pci_bus_reset pci_reset_bridge_secondary_bus pcibios_reset_secondary_bus (weak) pci_reset_secondary_bus pci_reset_bus (no caller) pci_probe_reset_bus (probe =1) pci_bus_reset pci_reset_bridge_secondary_bus pcibios_reset_secondary_bus (weak) pci_reset_secondary_bus -- Sinan Kaya Qualcomm Datacenter Technologies, Inc. as an affiliate of Qualcomm Technologies, Inc. Qualcomm Technologies, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project. -- 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
