Hi all, On Tue, 8 Dec 2020 13:56:20 +1100 Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx> wrote: > > Today's linux-next merge of the amdgpu tree got a conflict in: > > drivers/pci/pcie/err.c > > between commits: > > 8f1bbfbc3596 ("PCI/ERR: Rename reset_link() to reset_subordinates()") > 0791721d8007 ("PCI/ERR: Use "bridge" for clarity in pcie_do_recovery()") > 05e9ae19ab83 ("PCI/ERR: Add pci_walk_bridge() to pcie_do_recovery()") > > from the pci tree and commit: > > 36a8901e900a ("PCI/ERR: Fix reset logic in pcie_do_recovery() call") > > from the amdgpu tree. > > I fixed it up (I think - see below) and can carry the fix as > necessary. This is now fixed as far as linux-next is concerned, but any > non trivial conflicts should be mentioned to your upstream maintainer > when your tree is submitted for merging. You may also want to consider > cooperating with the maintainer of the conflicting tree to minimise any > particularly complex conflicts. > > > diff --cc drivers/pci/pcie/err.c > index 510f31f0ef6d,4a2735b70fa6..000000000000 > --- a/drivers/pci/pcie/err.c > +++ b/drivers/pci/pcie/err.c > @@@ -146,61 -146,49 +146,82 @@@ out > return 0; > } > > +/** > + * pci_walk_bridge - walk bridges potentially AER affected > + * @bridge: bridge which may be a Port, an RCEC, or an RCiEP > + * @cb: callback to be called for each device found > + * @userdata: arbitrary pointer to be passed to callback > + * > + * If the device provided is a bridge, walk the subordinate bus, including > + * any bridged devices on buses under this bus. Call the provided callback > + * on each device found. > + * > + * If the device provided has no subordinate bus, e.g., an RCEC or RCiEP, > + * call the callback on the device itself. > + */ > +static void pci_walk_bridge(struct pci_dev *bridge, > + int (*cb)(struct pci_dev *, void *), > + void *userdata) > +{ > + if (bridge->subordinate) > + pci_walk_bus(bridge->subordinate, cb, userdata); > + else > + cb(bridge, userdata); > +} > + > pci_ers_result_t pcie_do_recovery(struct pci_dev *dev, > - pci_channel_state_t state, > - pci_ers_result_t (*reset_link)(struct pci_dev *pdev)) > + pci_channel_state_t state, > + pci_ers_result_t (*reset_subordinates)(struct pci_dev *pdev)) > { > + int type = pci_pcie_type(dev); > + struct pci_dev *bridge; > pci_ers_result_t status = PCI_ERS_RESULT_CAN_RECOVER; > - struct pci_bus *bus; > + struct pci_host_bridge *host = pci_find_host_bridge(dev->bus); > > /* > - * Error recovery runs on all subordinates of the first downstream port. > - * If the downstream port detected the error, it is cleared at the end. > + * If the error was detected by a Root Port, Downstream Port, RCEC, > + * or RCiEP, recovery runs on the device itself. For Ports, that > + * also includes any subordinate devices. > + * > + * If it was detected by another device (Endpoint, etc), recovery > + * runs on the device and anything else under the same Port, i.e., > + * everything under "bridge". > */ > - if (!(pci_pcie_type(dev) == PCI_EXP_TYPE_ROOT_PORT || > - pci_pcie_type(dev) == PCI_EXP_TYPE_DOWNSTREAM)) > - dev = dev->bus->self; > - bus = dev->subordinate; > + if (type == PCI_EXP_TYPE_ROOT_PORT || > + type == PCI_EXP_TYPE_DOWNSTREAM || > + type == PCI_EXP_TYPE_RC_EC || > + type == PCI_EXP_TYPE_RC_END) > + bridge = dev; > + else > + bridge = pci_upstream_bridge(dev); > > - pci_dbg(dev, "broadcast error_detected message\n"); > + pci_dbg(bridge, "broadcast error_detected message\n"); > if (state == pci_channel_io_frozen) { > - pci_walk_bus(bus, report_frozen_detected, &status); > + pci_walk_bridge(bridge, report_frozen_detected, &status); > + /* > + * After resetting the link using reset_link() call, the > + * possible value of error status is either > + * PCI_ERS_RESULT_DISCONNECT (failure case) or > + * PCI_ERS_RESULT_NEED_RESET (success case). > + * So ignore the return value of report_error_detected() > + * call for fatal errors. > + * > + * In EDR mode, since AER and DPC Capabilities are owned by > + * firmware, reported_error_detected() will return error > + * status PCI_ERS_RESULT_NO_AER_DRIVER. Continuing > + * pcie_do_recovery() with error status as > + * PCI_ERS_RESULT_NO_AER_DRIVER will report recovery failure > + * irrespective of recovery status. But successful reset_link() > + * call usually recovers all fatal errors. So ignoring the > + * status result of report_error_detected() also helps EDR based > + * error recovery. > + */ > - status = reset_link(dev); > + status = reset_subordinates(bridge); > - if (status != PCI_ERS_RESULT_RECOVERED) { > + if (status == PCI_ERS_RESULT_RECOVERED) { > + status = PCI_ERS_RESULT_NEED_RESET; > + } else { > + status = PCI_ERS_RESULT_DISCONNECT; > - pci_warn(dev, "link reset failed\n"); > + pci_warn(bridge, "subordinate device reset failed\n"); > goto failed; > } > } else { > @@@ -215,13 -203,25 +236,25 @@@ > > if (status == PCI_ERS_RESULT_NEED_RESET) { > /* > - * TODO: Should call platform-specific > - * functions to reset slot before calling > - * drivers' slot_reset callbacks? > + * TODO: Optimize the call to pci_reset_bus() > + * > + * There are two components to pci_reset_bus(). > + * > + * 1. Do platform specific slot/bus reset. > + * 2. Save/Restore all devices in the bus. > + * > + * For hotplug capable devices and fatal errors, > + * device is already in reset state due to link > + * reset. So repeating platform specific slot/bus > + * reset via pci_reset_bus() call is redundant. So > + * can optimize this logic and conditionally call > + * pci_reset_bus(). > */ > + pci_reset_bus(dev); > + > status = PCI_ERS_RESULT_RECOVERED; > - pci_dbg(dev, "broadcast slot_reset message\n"); > - pci_walk_bus(bus, report_slot_reset, &status); > + pci_dbg(bridge, "broadcast slot_reset message\n"); > + pci_walk_bridge(bridge, report_slot_reset, &status); > } > > if (status != PCI_ERS_RESULT_RECOVERED) Just a reminder that this conflict still exists (the amdgpu tree commit is now 400b308d388a). -- Cheers, Stephen Rothwell
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