Re: [PATCH V4 7/7] PCI: Handle link reset via hotplug if supported

Andy Shevchenko
2018-06-29T21:39:03Z

On Thu, Jun 28, 2018 at 10:31 PM, Sinan Kaya <okaya@codeaurora.org> wrote:
> If a bridge supports hotplug and observes a PCIe fatal error, the following
> events happen:
>
> 1. AER driver removes the devices from PCI tree on fatal error
> 2. AER driver brings down the link by issuing a secondary bus reset waits
> for the link to come up.
> 3. Hotplug driver observes a link down interrupt
> 4. Hotplug driver tries to remove the devices waiting for the rescan lock
> but devices are already removed by the AER driver and AER driver is waiting
> for the link to come back up.
> 5. AER driver tries to re-enumerate devices after polling for the link
> state to go up.
> 6. Hotplug driver obtains the lock and tries to remove the devices again.
>
> If a bridge is a hotplug capable bridge, bounce the error handling to the
> hotplug driver so that hotplug driver can mask link up/down interrupts
> while performing a secondary bus reset.

> +static pci_ers_result_t pciehp_reset_link(struct pci_dev *pdev)
> +{
> + struct pcie_device *pciedev;
> + struct controller *ctrl;
> + struct device *devhp;
> + struct slot *slot;
> + int rc;
> +
> + devhp = pcie_port_find_device(pdev, PCIE_PORT_SERVICE_HP);
> + pciedev = to_pcie_device(devhp);
> + ctrl = get_service_data(pciedev);
> + slot = ctrl->slot;
> +
> + rc = reset_slot(slot->hotplug_slot, 0);
> +
> + return !rc ? PCI_ERS_RESULT_RECOVERED : PCI_ERS_RESULT_DISCONNECT;

Would it be better to

return rc ? ..._DISCONNECT : ..._RECOVERED; ?

> +}

--
With Best Regards,
Andy Shevchenko