sathyanarayanan.kuppuswamy@xxxxxxxxxxxxxxx wrote: >From: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@xxxxxxxxxxxxxxx> > >Fatal (DPC) error recovery is currently broken for non-hotplug >capable devices. With current implementation, after successful >fatal error recovery, non-hotplug capable device state won't be >restored properly. You can find related issues in following links. > >https://lkml.org/lkml/2020/5/27/290 >https://lore.kernel.org/linux-pci/12115.1588207324@famine/ >https://lkml.org/lkml/2020/3/28/328 > >Current fatal error recovery implementation relies on hotplug handler >for detaching/re-enumerating the affected devices/drivers on DLLSC >state changes. So when dealing with non-hotplug capable devices, >recovery code does not restore the state of the affected devices >correctly. Correct implementation should call report_slot_reset() >function after resetting the link to restore the state of the >device/driver. > >So use PCI_ERS_RESULT_NEED_RESET as error status for successful >reset_link() operation and use PCI_ERS_RESULT_DISCONNECT for failure >case. PCI_ERS_RESULT_NEED_RESET error state will ensure slot_reset() >is called after reset link operation which will also fix the above >mentioned issue. > >[original patch is from jay.vosburgh@xxxxxxxxxxxxx] >[original patch link https://lore.kernel.org/linux-pci/12115.1588207324@famine/] >Fixes: 6d2c89441571 ("PCI/ERR: Update error status after reset_link()") >Signed-off-by: Jay Vosburgh <jay.vosburgh@xxxxxxxxxxxxx> >Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@xxxxxxxxxxxxxxx> I've tested this patch set on one of our test machines, and it resolves the issue. I plan to test with other systems tomorrow. -J >--- > drivers/pci/pcie/err.c | 24 ++++++++++++++++++++++-- > 1 file changed, 22 insertions(+), 2 deletions(-) > >diff --git a/drivers/pci/pcie/err.c b/drivers/pci/pcie/err.c >index 14bb8f54723e..5fe8561c7185 100644 >--- a/drivers/pci/pcie/err.c >+++ b/drivers/pci/pcie/err.c >@@ -165,8 +165,28 @@ pci_ers_result_t pcie_do_recovery(struct pci_dev *dev, > pci_dbg(dev, "broadcast error_detected message\n"); > if (state == pci_channel_io_frozen) { > pci_walk_bus(bus, report_frozen_detected, &status); >- status = reset_link(dev); >- if (status != PCI_ERS_RESULT_RECOVERED) { >+ /* >+ * 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. Instead use >+ * PCI_ERS_RESULT_NEED_RESET as initial status value. >+ * >+ * Ignoring the status return value of report_error_detected() >+ * call will also help in case of EDR mode based error >+ * recovery. In EDR mode AER and DPC Capabilities are owned by >+ * firmware and hence report_error_detected() call will possibly >+ * return PCI_ERS_RESULT_NO_AER_DRIVER. So if we don't ignore >+ * the return value of report_error_detected() then >+ * pcie_do_recovery() would report incorrect status after >+ * successful recovery. Ignoring PCI_ERS_RESULT_NO_AER_DRIVER >+ * in non EDR case should not have any functional impact. >+ */ >+ status = PCI_ERS_RESULT_NEED_RESET; >+ if (reset_link(dev) != PCI_ERS_RESULT_RECOVERED) { >+ status = PCI_ERS_RESULT_DISCONNECT; > pci_warn(dev, "link reset failed\n"); > goto failed; > } >-- >2.17.1 > --- -Jay Vosburgh, jay.vosburgh@xxxxxxxxxxxxx
