[+cc Rafael, linux-pm; sorry forgot this last time]
On Fri, Apr 22, 2022 at 05:24:36PM -0500, Bjorn Helgaas wrote: > On Fri, Apr 08, 2022 at 11:31:58PM +0800, Kai-Heng Feng wrote: > > On Intel Alder Lake platforms, Thunderbolt entering D3cold can cause > > some errors reported by AER: > > [ 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 Base Spec 5.0, section 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). > > Help me walk through what's happening here, because I'm never very > confident about how error reporting works. I *think* the Unsupported > Request error means some request was in progress and was not > completed. I don't think a link going down should by itself cause > an Unsupported Request error because there's no *request*. > > I have a theory about what happened here. Decoding the TLP Header > (from PCIe r6.0, sec 2.2.1.1, 2.2.8.10) gives: > > 34000000 (0011 0100 ...): > Fmt 001 4 DW header, no data > Type 1 0100 Msg, Local - Terminate at Receiver > > 08000052 (0800 ... 0101 0010) > Requester ID 0800 00:08.0 > Message Code 0101 0010 PTM Request > > From your lspci in bugzilla, 08:00 has PTM enabled. So my theory is > that: > > - 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 > > So I suspect we should disable PTM on 08:00.0 before putting it in a > low-power state. If you manually disable PTM on 08:00.0, do these > errors stop happening? > > 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). > > Nit: can you remove the timestamps from the log? They add clutter but > no useful information. > > [1] https://git.kernel.org/linus/a697f072f5da > > > Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=215453 > > Reviewed-by: Mika Westerberg <mika.westerb...@linux.intel.com> > > Signed-off-by: Kai-Heng Feng <kai.heng.f...@canonical.com> > > --- > > v4: > > - Explicitly states the spec version. > > - Wording change. > > > > v3: > > - Remove reference to ACS. > > - Wording change. > > > > v2: > > - Wording change. > > > > drivers/pci/pcie/aer.c | 31 +++++++++++++++++++++++++------ > > 1 file changed, 25 insertions(+), 6 deletions(-) > > > > diff --git a/drivers/pci/pcie/aer.c b/drivers/pci/pcie/aer.c > > index 9fa1f97e5b270..e4e9d4a3098d7 100644 > > --- a/drivers/pci/pcie/aer.c > > +++ b/drivers/pci/pcie/aer.c > > @@ -1367,6 +1367,22 @@ 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 > > @@ -1433,12 +1449,15 @@ static pci_ers_result_t aer_root_reset(struct > > pci_dev *dev) > > } > > > > static struct pcie_port_service_driver aerdriver = { > > - .name = "aer", > > - .port_type = PCIE_ANY_PORT, > > - .service = PCIE_PORT_SERVICE_AER, > > - > > - .probe = aer_probe, > > - .remove = aer_remove, > > + .name = "aer", > > + .port_type = PCIE_ANY_PORT, > > + .service = PCIE_PORT_SERVICE_AER, > > + .probe = aer_probe, > > + .suspend = aer_suspend, > > + .resume = aer_resume, > > + .runtime_suspend = aer_suspend, > > + .runtime_resume = aer_resume, > > + .remove = aer_remove, > > }; > > > > /** > > -- > > 2.34.1 > >
