On Fri, Jun 25, 2021 at 03:38:41PM -0500, stuart hayes wrote:
> I have a system that is failing to recover after an EDR event with (or
> without...) this patch. It looks like the problem is similar to what this
> patch is trying to fix, except that on my system, the hotplug port is
> downstream of the root port that has DPC, so the "link down" event on it is
> not being ignored. So the hotplug code disables the slot (which contains an
> NVMe device on this system) while the nvme driver is trying to use it, which
> results in a failed recovery and another EDR event, and the kernel ends up
> with the DPC trigger status bit set in the root port, so everything
> downstream is gone.
>
> I added the hack below so the hotplug code will ignore the "link down"
> events on the ports downstream of the root port during DPC recovery, and it
> recovers no problem. (I'm not proposing this as a correct fix.)
Could you test if the below patch fixes the issue?
Note, this is a hack as well, but I can turn it into a proper patch
if it works as expected.
Thanks!
Lukas
-- >8 --
diff --git a/drivers/pci/pcie/portdrv_pci.c b/drivers/pci/pcie/portdrv_pci.c
index c7ff1eea225a..893c7ae1a54d 100644
--- a/drivers/pci/pcie/portdrv_pci.c
+++ b/drivers/pci/pcie/portdrv_pci.c
@@ -160,6 +160,10 @@ static pci_ers_result_t pcie_portdrv_error_detected(struct pci_dev *dev,
static pci_ers_result_t pcie_portdrv_slot_reset(struct pci_dev *dev)
{
+ if (dev->is_hotplug_bridge)
+ pcie_capability_write_word(dev, PCI_EXP_SLTSTA,
+ PCI_EXP_SLTSTA_DLLSC);
+
pci_restore_state(dev);
pci_save_state(dev);
return PCI_ERS_RESULT_RECOVERED;
