On Thu, Jan 28, 2021 at 01:31:00AM +0800, Kai-Heng Feng wrote:
> Commit 50310600ebda ("iommu/vt-d: Enable PCI ACS for platform opt in
> hint") enables ACS, and some platforms lose its NVMe after resume from
> firmware:
> [ 50.947816] pcieport 0000:00:1b.0: DPC: containment event, status:0x1f01 source:0x0000
> [ 50.947817] pcieport 0000:00:1b.0: DPC: unmasked uncorrectable error detected
> [ 50.947829] pcieport 0000:00:1b.0: PCIe Bus Error: severity=Uncorrected (Non-Fatal), type=Transaction Layer, (Receiver ID)
> [ 50.947830] pcieport 0000:00:1b.0: device [8086:06ac] error status/mask=00200000/00010000
> [ 50.947831] pcieport 0000:00:1b.0: [21] ACSViol (First)
> [ 50.947841] pcieport 0000:00:1b.0: AER: broadcast error_detected message
> [ 50.947843] nvme nvme0: frozen state error detected, reset controller
>
> It happens right after ACS gets enabled during resume.
>
> To prevent that from happening, disable AER interrupt and enable it on
> system suspend and resume, respectively.
Lots of questions here. Maybe this is what we'll end up doing, but I
am curious about why the error is reported in the first place.
Is this a consequence of the link going down and back up?
Is it consequence of the device doing a DMA when it shouldn't?
Are we doing something in the wrong order during suspend? Or maybe
resume, since I assume the error is reported during resume?
If we *do* take the error, why doesn't DPC recovery work?
> Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=209149
> Fixes: 50310600ebda ("iommu/vt-d: Enable PCI ACS for platform opt in hint")
> Signed-off-by: Kai-Heng Feng <kai.heng.feng@xxxxxxxxxxxxx>
> ---
> drivers/pci/pcie/aer.c | 18 ++++++++++++++++++
> 1 file changed, 18 insertions(+)
>
> diff --git a/drivers/pci/pcie/aer.c b/drivers/pci/pcie/aer.c
> index 77b0f2c45bc0..0e9a85530ae6 100644
> --- a/drivers/pci/pcie/aer.c
> +++ b/drivers/pci/pcie/aer.c
> @@ -1365,6 +1365,22 @@ static int aer_probe(struct pcie_device *dev)
> return 0;
> }
>
> +static int aer_suspend(struct pcie_device *dev)
> +{
> + struct aer_rpc *rpc = get_service_data(dev);
> +
> + aer_disable_rootport(rpc);
> + return 0;
> +}
> +
> +static int aer_resume(struct pcie_device *dev)
> +{
> + struct aer_rpc *rpc = get_service_data(dev);
> +
> + aer_enable_rootport(rpc);
> + return 0;
> +}
> +
> /**
> * aer_root_reset - reset Root Port hierarchy, RCEC, or RCiEP
> * @dev: pointer to Root Port, RCEC, or RCiEP
> @@ -1437,6 +1453,8 @@ static struct pcie_port_service_driver aerdriver = {
> .service = PCIE_PORT_SERVICE_AER,
>
> .probe = aer_probe,
> + .suspend = aer_suspend,
> + .resume = aer_resume,
> .remove = aer_remove,
> };
>
> --
> 2.29.2
>
