On Wed, Jul 06, 2022 at 08:32:44PM +0800, Kai-Heng Feng wrote: > On Intel Alder Lake platforms, Thunderbolt entering D3cold can cause > some errors reported by AER: > pcieport 0000:00:1d.0: AER: Uncorrected (Non-Fatal) error received: 0000:00:1d.0 > pcieport 0000:00:1d.0: PCIe Bus Error: severity=Uncorrected (Non-Fatal), type=Transaction Layer, (Requester ID) > pcieport 0000:00:1d.0: device [8086:7ab0] error status/mask=00100000/00004000 > pcieport 0000:00:1d.0: [20] UnsupReq (First) > pcieport 0000:00:1d.0: AER: TLP Header: 34000000 08000052 00000000 00000000 > thunderbolt 0000:0a:00.0: AER: can't recover (no error_detected callback) > xhci_hcd 0000:3e:00.0: AER: can't recover (no error_detected callback) > pcieport 0000:00:1d.0: AER: device recovery failed > > In addition to that, it can also block system from suspending when > a Thunderbolt dock is attached to the same system. > > The original approach [1] is to disable AER and DPC when link is in > L2/L3 Ready, L2 and L3, but Bjorn identified the root cause is the Unsupported > Request: > - 08:00.0 sent a PTM Request Message (a Posted Request) > - 00:1d.0 received the PTM Request Message > - The link transitioned to DL_Down > - Per sec 2.9.1, 00:1d.0 discarded the Request and reported an > Unsupported Request > - Or, per sec 6.21.3, if 00:1d.0 received a PTM Request when its > own PTM Enable was clear, it would also be treated as an > Unsupported Request > > And further: 'David did something like this [1], but just for Root Ports. That > looks wrong to me because sec 6.21.3 says we should not have PTM enabled in an > Upstream Port (i.e., in a downstream device like 08:00.0) unless it is already > enabled in the Downstream Port (i.e., in the Root Port 00:1d.0).' > > So also disable upstream port PTM to make the PCI driver conform to the spec > and solve the issue. > > [1] https://lore.kernel.org/all/20220408153159.106741-1-kai.heng.feng@xxxxxxxxxxxxx/ > [2] https://lore.kernel.org/all/20220422222433.GA1464120@bhelgaas/ > Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=215453 > Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=216210 > Suggested-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx> > Cc: David E. Box <david.e.box@xxxxxxxxxxxxxxx> > Cc: Sathyanarayanan Kuppuswamy <sathyanarayanan.kuppuswamy@xxxxxxxxxxxxxxx> > > Signed-off-by: Kai-Heng Feng <kai.heng.feng@xxxxxxxxxxxxx> Reviewed-by: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx>
