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Date:   Tue, 12 May 2020 12:20:30 -0700
From:   Jay Vosburgh <>
        Yicong Yang <>,
        liudongdong 00290354 <>,
        Linuxarm <>
Subject: Re: [PATCH v1 1/1] PCI/ERR: Handle fatal error recovery for non-hotplug capable devices wrote:

>From: Kuppuswamy Sathyanarayanan <>
>If there are non-hotplug capable devices connected to a given
>port, then during the fatal error recovery(triggered by DPC or
>AER), after calling reset_link() function, we cannot rely on
>hotplug handler to detach and re-enumerate the device drivers
>in the affected bus. Instead, we will have to let the error
>recovery handler call report_slot_reset() for all devices in
>the bus to notify about the reset operation. Although this is
>only required for non hot-plug capable devices, doing it for
>hotplug capable devices should not affect the functionality.


	Does the patch below also resolve the issue for you, as with
your changed version of my original patch?


>Along with above issue, this fix also applicable to following
>Commit 6d2c89441571 ("PCI/ERR: Update error status after
>reset_link()") added support to store status of reset_link()
>call. Although this fixed the error recovery issue observed if
>the initial value of error status is PCI_ERS_RESULT_DISCONNECT
>or PCI_ERS_RESULT_NO_AER_DRIVER, it also discarded the status
>result from report_frozen_detected. This can cause a failure to
>recover if _NEED_RESET is returned by report_frozen_detected and
>report_slot_reset is not invoked.
>Such an event can be induced for testing purposes by reducing the
>Max_Payload_Size of a PCIe bridge to less than that of a device
>downstream from the bridge, and then initiating I/O through the
>device, resulting in oversize transactions.  In the presence of DPC,
>this results in a containment event and attempted reset and recovery
>via pcie_do_recovery.  After 6d2c89441571 report_slot_reset is not
>invoked, and the device does not recover.
>[original patch is from]
>[original patch link]
>Fixes: 6d2c89441571 ("PCI/ERR: Update error status after reset_link()")
>Signed-off-by: Jay Vosburgh <>
>Signed-off-by: Kuppuswamy Sathyanarayanan <>
> drivers/pci/pcie/err.c | 19 +++++++++++++++----
> 1 file changed, 15 insertions(+), 4 deletions(-)
>diff --git a/drivers/pci/pcie/err.c b/drivers/pci/pcie/err.c
>index 14bb8f54723e..db80e1ecb2dc 100644
>--- a/drivers/pci/pcie/err.c
>+++ b/drivers/pci/pcie/err.c
>@@ -165,13 +165,24 @@ 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) {
>+	} else {
>+		pci_walk_bus(bus, report_normal_detected, &status);
>+	}
>+	if (status == PCI_ERS_RESULT_NEED_RESET) {
>+		if (reset_link) {
>+			if (reset_link(dev) != PCI_ERS_RESULT_RECOVERED)
>+		} else {
>+			if (pci_bus_error_reset(dev))
>+		}
>+		if (status == PCI_ERS_RESULT_DISCONNECT) {
> 			pci_warn(dev, "link reset failed\n");
> 			goto failed;
> 		}
>-	} else {
>-		pci_walk_bus(bus, report_normal_detected, &status);
> 	}
> 	if (status == PCI_ERS_RESULT_CAN_RECOVER) {

	-Jay Vosburgh,

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