lkml.org 
[lkml]   [2021]   [Aug]   [9]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] PCI/portdrv: Disallow runtime suspend when waekup is required but PME service isn't supported
[cc += Mika]

On Mon, Aug 09, 2021 at 12:24:12PM +0800, Kai-Heng Feng wrote:
> Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=213873

The last comment on this bugzilla says "BIOS will fix this."
and the status is RESOLVED WILL_NOT_FIX.

Why is the patch still necessary?


> Some platforms cannot detect ethernet hotplug once its upstream port is
> runtime suspended because PME isn't enabled in _OSC.

If PME is not handled natively, why does the NIC runtime suspend?
Shouldn't this be fixed in the NIC driver by keeping the device
runtime active if PME cannot be used?


> Disallow port runtime suspend when any child device requires wakeup, so
> pci_pme_list_scan() can still read the PME status from the devices
> behind the port.

pci_pme_list_scan() is for broken devices which fail to signal PME.
Is this NIC really among them or does PME fail merely because it's not
granted to OSPM?


> --- a/drivers/pci/pcie/portdrv_pci.c
> +++ b/drivers/pci/pcie/portdrv_pci.c
> @@ -59,14 +59,30 @@ static int pcie_port_runtime_suspend(struct device *dev)
> return pcie_port_device_runtime_suspend(dev);
> }
>
> +static int pcie_port_wakeup_check(struct device *dev, void *data)
> +{
> + struct pci_dev *pdev = to_pci_dev(dev);
> +
> + if (!pdev)
> + return 0;
> +
> + return pdev->wakeup_prepared;
> +}
> +
> static int pcie_port_runtime_idle(struct device *dev)
> {
> + struct pci_dev *pdev = to_pci_dev(dev);
> +
> + if (!pcie_port_find_device(pdev, PCIE_PORT_SERVICE_PME) &&
> + device_for_each_child(dev, NULL, pcie_port_wakeup_check))
> + return -EBUSY;
> +
> /*
> * Assume the PCI core has set bridge_d3 whenever it thinks the port
> * should be good to go to D3. Everything else, including moving
> * the port to D3, is handled by the PCI core.
> */
> - return to_pci_dev(dev)->bridge_d3 ? 0 : -EBUSY;
> + return pdev->bridge_d3 ? 0 : -EBUSY;

If an additional check is necessary for this issue, it should be
integrated into pci_dev_check_d3cold() instead of pcie_port_runtime_idle().

Thanks,

Lukas

\
 
 \ /
  Last update: 2021-08-09 11:48    [W:0.184 / U:0.200 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site