From: sathyanarayanan.kuppuswamy@linux.intel.com
To: bhelgaas@google.com
Cc: linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org,
ashok.raj@intel.com, sathyanarayanan.kuppuswamy@linux.intel.com,
Jay Vosburgh <jay.vosburgh@canonical.com>
Subject: [PATCH v2 1/2] PCI/ERR: Fix fatal error recovery for non-hotplug capable devices
Date: Thu, 4 Jun 2020 14:50:01 -0700 [thread overview]
Message-ID: <ce417fbf81a8a46a89535f44b9224ee9fbb55a29.1591307288.git.sathyanarayanan.kuppuswamy@linux.intel.com> (raw)
From: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
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@canonical.com]
[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@canonical.com>
Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
---
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
next reply other threads:[~2020-06-04 21:50 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-04 21:50 sathyanarayanan.kuppuswamy [this message]
2020-06-04 21:50 ` [PATCH v2 2/2] PCI/ERR: Add reset support for non fatal errors sathyanarayanan.kuppuswamy
2020-06-28 12:57 ` Yicong Yang
2020-06-05 4:47 ` [PATCH v2 1/2] PCI/ERR: Fix fatal error recovery for non-hotplug capable devices Jay Vosburgh
2020-06-24 18:52 ` Jay Vosburgh
2020-06-28 12:59 ` Yicong Yang
2020-07-14 23:08 ` Bjorn Helgaas
2020-07-16 1:54 ` Kuppuswamy, Sathyanarayanan
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