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Subject[PATCH v18 03/11] PCI/DPC: Fix DPC recovery issue in non hotplug case
Date
From: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>

If hotplug is supported, during DPC event, hotplug
driver would remove the affected devices and detach
the drivers on DLLSC link down event and will
re-enumerate it once the DPC recovery is handled
and link comes back online (on DLLSC LINK up event).
Hence we don't depend on .mmio_enabled or .slot_reset
callbacks in error recovery handler to restore the
device.

But if hotplug is not supported/enabled, then we need
to let the error recovery handler attempt
the recovery of the devices using slot reset.

So if hotplug is not supported, then instead of
returning PCI_ERS_RESULT_RECOVERED, return
PCI_ERS_RESULT_NEED_RESET.

Also modify the way error recovery handler processes
the recovery value.

Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
---
drivers/pci/pcie/dpc.c | 8 ++++++++
drivers/pci/pcie/err.c | 5 +++--
2 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/drivers/pci/pcie/dpc.c b/drivers/pci/pcie/dpc.c
index e06f42f58d3d..0e356ed0d73f 100644
--- a/drivers/pci/pcie/dpc.c
+++ b/drivers/pci/pcie/dpc.c
@@ -13,6 +13,7 @@
#include <linux/interrupt.h>
#include <linux/init.h>
#include <linux/pci.h>
+#include <linux/pci_hotplug.h>

#include "portdrv.h"
#include "../pci.h"
@@ -144,6 +145,13 @@ static pci_ers_result_t dpc_reset_link(struct pci_dev *pdev)
if (!pcie_wait_for_link(pdev, true))
return PCI_ERS_RESULT_DISCONNECT;

+ /*
+ * If hotplug is not supported/enabled then let the device
+ * recover using slot reset.
+ */
+ if (!hotplug_is_native(pdev))
+ return PCI_ERS_RESULT_NEED_RESET;
+
return PCI_ERS_RESULT_RECOVERED;
}

diff --git a/drivers/pci/pcie/err.c b/drivers/pci/pcie/err.c
index 1ac57e9e1e71..6e52591a4722 100644
--- a/drivers/pci/pcie/err.c
+++ b/drivers/pci/pcie/err.c
@@ -178,7 +178,8 @@ static pci_ers_result_t reset_link(struct pci_dev *dev, u32 service)
return PCI_ERS_RESULT_DISCONNECT;
}

- if (status != PCI_ERS_RESULT_RECOVERED) {
+ if ((status != PCI_ERS_RESULT_RECOVERED) &&
+ (status != PCI_ERS_RESULT_NEED_RESET)) {
pci_printk(KERN_DEBUG, dev, "link reset at upstream device %s failed\n",
pci_name(dev));
return PCI_ERS_RESULT_DISCONNECT;
@@ -206,7 +207,7 @@ void pcie_do_recovery(struct pci_dev *dev, enum pci_channel_state state,
if (state == pci_channel_io_frozen) {
pci_walk_bus(bus, report_frozen_detected, &status);
status = reset_link(dev, service);
- if (status != PCI_ERS_RESULT_RECOVERED)
+ if (status == PCI_ERS_RESULT_DISCONNECT)
goto failed;
} else {
pci_walk_bus(bus, report_normal_detected, &status);
--
2.17.1
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