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Date:   Thu, 27 Jan 2022 08:30:21 +0200
From:   Mika Westerberg <mika.westerberg@linux.intel.com>
To:     Kai-Heng Feng <kai.heng.feng@canonical.com>
Cc:     bhelgaas@google.com, koba.ko@canonical.com,
        Russell Currey <ruscur@russell.cc>,
        Oliver O'Halloran <oohall@gmail.com>,
        Lalithambika Krishnakumar <lalithambika.krishnakumar@intel.com>,
        Lu Baolu <baolu.lu@linux.intel.com>,
        Joerg Roedel <jroedel@suse.de>, linuxppc-dev@lists.ozlabs.org,
        linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 1/2] PCI/AER: Disable AER service when link is in
 L2/L3 ready, L2 and L3 state
Message-ID: <YfI7/X15bl+Ac19A@lahna>
References: <20220127025418.1989642-1-kai.heng.feng@canonical.com>
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On Thu, Jan 27, 2022 at 10:54:17AM +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
> S3:
> [   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.
> 
> There's another case, when Thunderbolt reaches D3cold:
> [   30.100211] pcieport 0000:00:1d.0: AER: Uncorrected (Non-Fatal) error received: 0000:00:1d.0
> [   30.100251] pcieport 0000:00:1d.0: PCIe Bus Error: severity=Uncorrected (Non-Fatal), type=Transaction Layer, (Requester ID)
> [   30.100256] pcieport 0000:00:1d.0:   device [8086:7ab0] error status/mask=00100000/00004000
> [   30.100262] pcieport 0000:00:1d.0:    [20] UnsupReq               (First)
> [   30.100267] pcieport 0000:00:1d.0: AER:   TLP Header: 34000000 08000052 00000000 00000000
> [   30.100372] thunderbolt 0000:0a:00.0: AER: can't recover (no error_detected callback)
> [   30.100401] xhci_hcd 0000:3e:00.0: AER: can't recover (no error_detected callback)
> [   30.100427] pcieport 0000:00:1d.0: AER: device recovery failed
> 
> So disable AER service to avoid the noises from turning power rails
> on/off when the device is in low power states (D3hot and D3cold), as
> PCIe spec "5.2 Link State Power Management" states that TLP and DLLP
> transmission is disabled for a Link in L2/L3 Ready (D3hot), L2 (D3cold
> with aux power) and L3 (D3cold).
> 
> Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=209149
> Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=215453
> Fixes: 50310600ebda ("iommu/vt-d: Enable PCI ACS for platform opt in hint")
> Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>

Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>