Hello, I'm using Kernel 5.10 and am seeing a regression w.r.t. 5.4 kernel (I plan to try the latest kernel in some time). I have a thunderbolt SSD [1]. After the thunderbolt tunnels are created, it shows up as a PCIe NVME device (behind a PCIe switch internal to the SSD): localhost ~ # lspci -t -[0000:00]-+-00.0 +-02.0 +-04.0 +-05.0 +-07.0-[01-2b]-- +-07.1-[2c-56]-- +-07.2-[57-81]----00.0-[58-81]----01.0-[59-81]----00.0 <------ NVME (0000:59:00.0) +-08.0 +-0a.0 +-0d.0 +-0d.2 +-0d.3 +-14.0 +-14.2 +-14.3 +-15.0 +-15.1 +-15.2 +-15.3 +-16.0 +-19.0 +-19.1 +-1c.0-[82]----00.0 +-1c.7-[83]----00.0 +-1d.0-[84]----00.0 +-1e.0 +-1e.3 +-1f.0 +-1f.3 \-1f.5 localhost ~ # The PCI bus enumeration goes through fine, and the PCIe resource assignment is done correctly as far as I can see: 1423.813513] pcieport 0000:00:07.2: pciehp: Slot(5): Card present 1423.820263] pcieport 0000:00:07.2: pciehp: Slot(5): Link Up 1423.953045] pci 0000:57:00.0: [8086:15da] type 01 class 0x060400 1423.959875] pci 0000:57:00.0: enabling Extended Tags 1423.965653] pci 0000:57:00.0: supports D1 D2 1423.970433] pci 0000:57:00.0: PME# supported from D0 D1 D2 D3hot D3cold 1423.977900] pci 0000:57:00.0: 8.000 Gb/s available PCIe bandwidth, limited by 2.5 GT/s PCIe x4 link at 0000:00:07.2 (capable of 31.504 Gb/s with 8.0 GT/s PCIe x4 link) 1423.994843] pci 0000:57:00.0: Adding to iommu group 23 1424.004806] pci 0000:57:00.0: bridge configuration invalid ([bus 00-00]), reconfiguring 1424.013929] pci 0000:58:01.0: [8086:15da] type 01 class 0x060400 1424.020734] pci 0000:58:01.0: enabling Extended Tags 1424.026428] pci 0000:58:01.0: supports D1 D2 1424.031205] pci 0000:58:01.0: PME# supported from D0 D1 D2 D3hot D3cold 1424.038689] pci 0000:58:01.0: Adding to iommu group 24 1424.044651] pci 0000:57:00.0: PCI bridge to [bus 58-81] 1424.050512] pci 0000:57:00.0: bridge window [io 0x0000-0x0fff] 1424.057344] pci 0000:57:00.0: bridge window [mem 0x00000000-0x000fffff] 1424.064948] pci 0000:57:00.0: bridge window [mem 0x00000000-0x000fffff 64bit pref] 1424.073620] pci 0000:58:01.0: bridge configuration invalid ([bus 00-00]), reconfiguring 1424.082742] pci 0000:59:00.0: [144d:a808] type 00 class 0x010802 1424.089506] pci 0000:59:00.0: reg 0x10: [mem 0x00000000-0x00003fff 64bit] 1424.097437] pci 0000:59:00.0: 8.000 Gb/s available PCIe bandwidth, limited by 2.5 GT/s PCIe x4 link at 0000:00:07.2 (capable of 31.504 Gb/s with 8.0 GT/s PCIe x4 link) 1424.114209] pci 0000:59:00.0: Adding to iommu group 24 1424.122145] udevd[10117]: Process '/sbin/restorecon ' failed with exit code 255. 1424.124803] pci 0000:58:01.0: PCI bridge to [bus 59-81] 1424.136333] pci 0000:58:01.0: bridge window [io 0x0000-0x0fff] 1424.143169] pci 0000:58:01.0: bridge window [mem 0x00000000-0x000fffff] 1424.150774] pci 0000:58:01.0: bridge window [mem 0x00000000-0x000fffff 64bit pref] 1424.159446] pci_bus 0000:59: busn_res: [bus 59-81] end is updated to 81 1424.166856] pci_bus 0000:58: busn_res: [bus 58-81] end is updated to 81 1424.174272] pci 0000:58:01.0: bridge window [mem 0x00100000-0x001fffff 64bit pref] to [bus 59-81] add_size 100000 add_align 100000 1424.187411] pci 0000:58:01.0: bridge window [mem 0x00100000-0x001fffff] to [bus 59-81] add_size 100000 add_align 100000 1424.199481] pci 0000:57:00.0: bridge window [mem 0x00100000-0x001fffff 64bit pref] to [bus 58-81] add_size 100000 add_align 100000 1424.212609] pci 0000:57:00.0: bridge window [mem 0x00100000-0x001fffff] to [bus 58-81] add_size 100000 add_align 100000 1424.224678] pci 0000:57:00.0: BAR 8: assigned [mem 0xac200000-0xb83fffff] 1424.232269] pci 0000:57:00.0: BAR 9: assigned [mem 0x2b7c00000-0x2d3bfffff 64bit pref] 1424.241127] pci 0000:57:00.0: BAR 7: assigned [io 0x6000-0x7fff] 1424.247944] pci 0000:58:01.0: BAR 8: assigned [mem 0xac200000-0xb83fffff] 1424.255539] pci 0000:58:01.0: BAR 9: assigned [mem 0x2b7c00000-0x2d3bfffff 64bit pref] 1424.264396] pci 0000:58:01.0: BAR 7: assigned [io 0x6000-0x7fff] 1424.271209] pci 0000:59:00.0: BAR 0: assigned [mem 0xac200000-0xac203fff 64bit] <----- assigned 1424.279409] pci 0000:58:01.0: PCI bridge to [bus 59-81] 1424.285263] pci 0000:58:01.0: bridge window [io 0x6000-0x7fff] 1424.292089] pci 0000:58:01.0: bridge window [mem 0xac200000-0xb83fffff] 1424.299690] pci 0000:58:01.0: bridge window [mem 0x2b7c00000-0x2d3bfffff 64bit pref] 1424.308560] pci 0000:57:00.0: PCI bridge to [bus 58-81] 1424.314418] pci 0000:57:00.0: bridge window [io 0x6000-0x7fff] 1424.321251] pci 0000:57:00.0: bridge window [mem 0xac200000-0xb83fffff] 1424.328851] pci 0000:57:00.0: bridge window [mem 0x2b7c00000-0x2d3bfffff 64bit pref] 1424.337720] pcieport 0000:00:07.2: PCI bridge to [bus 57-81] 1424.344062] pcieport 0000:00:07.2: bridge window [io 0x6000-0x7fff] 1424.351377] pcieport 0000:00:07.2: bridge window [mem 0xac200000-0xb83fffff] 1424.359455] pcieport 0000:00:07.2: bridge window [mem 0x2b7c00000-0x2d3bfffff 64bit pref]1424.377279] pcieport 0000:57:00.0: enabling device (0000 -> 0003) 1424.393001] pcieport 0000:58:01.0: enabling device (0000 -> 0003) 1424.408363] pcieport 0000:58:01.0: pciehp: Slot #1 AttnBtn- PwrCtrl- MRL- AttnInd- PwrInd- HotPlug+ Surprise+ Interlock- NoCompl+ IbPresDis- LLActRep+ However, the PCIe NVME driver attaches fine only half the time, and refuses to attach the other 50% of the time: 1424.464958] nvme nvme1: pci function 0000:59:00.0 1424.470366] nvme 0000:59:00.0: enabling device (0000 -> 0002) 1424.477196] nvme nvme1: Removing after probe failure status: -19 Careful examination shows that the probe fails because the register accesses (in the memory space) made by the driver don't go through because the BAR register has been zeroed out somehow (lspci info at the end of the mail). On writing manually the BAR register again using setpci and re-attaching the driver, it works this time. So essentially the BAR register loses its value somehow. My theory is somehow the runtime PM is kicking in the wrong order, or when it is not supposed to, which is causing the BAR register to be wiped out. So I enabled the RPM traces via /sys/kernel/debug/tracing/events/rpm/enable. I noticed that in the failure scenarios, the PCIe NVME device was apparently runtime suspended at the time the driver was trying to attach to the device. In the successful scenarios, I don't see any of the PCIe device in that device hierarchy being suspended while the enumeration / driver attach is going on. My questions are: 1) Do I understand it right that I can conclude that the device 59:00.0 was runtime suspended between the following 2 prints in the tracelog? <...>-25917 [002] d..1 2612.612591: rpm_return_int: rpm_suspend+0x4cd/0x514:0000:59:00.0 ret=0 .... <was the device suspended here?> .... kworker/0:1-15 [000] d..1 2632.059915: rpm_return_int: rpm_resume+0x392/0x570:0000:59:00.0 ret=0 2) Is my understanding correct that any device should NOT be runtime suspended while a driver is trying to attach to the device? Where is this ensured (for e.g. for NVMEs)? Is this ensured by the driver core, or a device driver that is trying to probe a PCI device needs to ensure this? 3) So all downstream devices of a PCI bridge need to be suspended before it can be suspended (and vice versa for resume)? In other words, is ita bug if I notice that a PCI bridge is runtime suspended while any of its downstream devices are not? 4) Any suggestions for me to try? I have noticed that putting a lot of debug prints changes the situation (converts failing case into pass case) but may be that hints something to do with timing / race condition? Thanks, Rajat More details: [1] Product: https://www.amazon.com/gp/product/B07GBTY82P/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1 [2] Detailed lspci info for all devices in the PCI chain starting from root port and ending at end point (in successful case): 00:07.2 PCI bridge: Intel Corporation Device 462f (rev 03) (prog-if 00 [Normal decode]) Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx+ Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx- Latency: 0, Cache Line Size: 64 bytes Interrupt: pin C routed to IRQ 157 Bus: primary=00, secondary=57, subordinate=81, sec-latency=0 I/O behind bridge: 00006000-00007fff [size=8K] Memory behind bridge: ac200000-b83fffff [size=194M] Prefetchable memory behind bridge: 00000002b7c00000-00000002d3bfffff [size=448M] Secondary status: 66MHz- FastB2B- ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort+ <SERR- <PERR- BridgeCtl: Parity+ SERR+ NoISA- VGA- MAbort- >Reset- FastB2B- PriDiscTmr- SecDiscTmr- DiscTmrStat- DiscTmrSERREn- Capabilities: [40] Express (v2) Root Port (Slot+), MSI 00 DevCap: MaxPayload 128 bytes, PhantFunc 0 ExtTag- RBE+ DevCtl: Report errors: Correctable+ Non-Fatal+ Fatal+ Unsupported+ RlxdOrd- ExtTag- PhantFunc- AuxPwr- NoSnoop- MaxPayload 128 bytes, MaxReadReq 128 bytes DevSta: CorrErr- UncorrErr- FatalErr- UnsuppReq- AuxPwr+ TransPend- LnkCap: Port #4, Speed 2.5GT/s, Width x4, ASPM L1, Exit Latency L1 <64us ClockPM- Surprise- LLActRep+ BwNot+ ASPMOptComp+ LnkCtl: ASPM Disabled; RCB 64 bytes Disabled- CommClk+ ExtSynch- ClockPM- AutWidDis- BWInt- AutBWInt- LnkSta: Speed 2.5GT/s, Width x4, TrErr- Train- SlotClk+ DLActive+ BWMgmt+ ABWMgmt- SltCap: AttnBtn- PwrCtrl- MRL- AttnInd- PwrInd- HotPlug+ Surprise+ Slot #5, PowerLimit 0.000W; Interlock- NoCompl+ SltCtl: Enable: AttnBtn- PwrFlt- MRL- PresDet+ CmdCplt- HPIrq+ LinkChg+ Control: AttnInd Unknown, PwrInd Unknown, Power- Interlock- SltSta: Status: AttnBtn- PowerFlt- MRL- CmdCplt- PresDet+ Interlock- Changed: MRL- PresDet- LinkState+ RootCtl: ErrCorrectable- ErrNon-Fatal- ErrFatal- PMEIntEna+ CRSVisible- RootCap: CRSVisible- RootSta: PME ReqID 0000, PMEStatus- PMEPending- DevCap2: Completion Timeout: Range ABC, TimeoutDis+, LTR+, OBFF Via WAKE# ARIFwd+ AtomicOpsCap: Routing- 32bit- 64bit- 128bitCAS- DevCtl2: Completion Timeout: 50us to 50ms, TimeoutDis-, LTR+, OBFF Disabled ARIFwd- AtomicOpsCtl: ReqEn- EgressBlck- LnkCtl2: Target Link Speed: 2.5GT/s, EnterCompliance- SpeedDis- Transmit Margin: Normal Operating Range, EnterModifiedCompliance- ComplianceSOS- Compliance De-emphasis: -6dB LnkSta2: Current De-emphasis Level: -3.5dB, EqualizationComplete-, EqualizationPhase1- EqualizationPhase2-, EqualizationPhase3-, LinkEqualizationRequest- Capabilities: [80] MSI: Enable+ Count=1/1 Maskable- 64bit+ Address: 00000000fee00000 Data: 0000 Capabilities: [90] Subsystem: Intel Corporation Device 7270 Capabilities: [a0] Power Management version 3 Flags: PMEClk- DSI- D1- D2- AuxCurrent=0mA PME(D0+,D1-,D2-,D3hot+,D3cold+) Status: D0 NoSoftRst- PME-Enable- DSel=0 DScale=0 PME- Capabilities: [100 v1] Advanced Error Reporting UESta: DLP- SDES- TLP- FCP- CmpltTO- CmpltAbrt- UnxCmplt- RxOF- MalfTLP- ECRC- UnsupReq- ACSViol- UEMsk: DLP- SDES- TLP- FCP- CmpltTO- CmpltAbrt- UnxCmplt- RxOF- MalfTLP- ECRC- UnsupReq- ACSViol- UESvrt: DLP+ SDES- TLP- FCP- CmpltTO- CmpltAbrt- UnxCmplt- RxOF+ MalfTLP+ ECRC- UnsupReq- ACSViol- CESta: RxErr- BadTLP- BadDLLP- Rollover- Timeout- NonFatalErr- CEMsk: RxErr- BadTLP- BadDLLP- Rollover- Timeout- NonFatalErr+ AERCap: First Error Pointer: 00, ECRCGenCap- ECRCGenEn- ECRCChkCap- ECRCChkEn- MultHdrRecCap- MultHdrRecEn- TLPPfxPres- HdrLogCap- HeaderLog: 00000000 00000000 00000000 00000000 RootCmd: CERptEn+ NFERptEn+ FERptEn+ RootSta: CERcvd- MultCERcvd- UERcvd- MultUERcvd- FirstFatal- NonFatalMsg- FatalMsg- IntMsg 0 ErrorSrc: ERR_COR: 0000 ERR_FATAL/NONFATAL: 0000 Capabilities: [220 v1] Access Control Services ACSCap: SrcValid+ TransBlk+ ReqRedir+ CmpltRedir+ UpstreamFwd+ EgressCtrl- DirectTrans- ACSCtl: SrcValid+ TransBlk+ ReqRedir+ CmpltRedir+ UpstreamFwd+ EgressCtrl- DirectTrans- Capabilities: [a00 v1] Downstream Port Containment DpcCap: INT Msg #0, RPExt+ PoisonedTLP- SwTrigger- RP PIO Log 0, DL_ActiveErr- DpcCtl: Trigger:0 Cmpl- INT- ErrCor- PoisonedTLP- SwTrigger- DL_ActiveErr- DpcSta: Trigger- Reason:00 INT- RPBusy- TriggerExt:00 RP PIO ErrPtr:1f Source: 0000 Capabilities: [a30 v1] #19 Capabilities: [a90 v1] #25 Capabilities: [ba0 v0] #15 Kernel driver in use: pcieport 57:00.0 PCI bridge: Intel Corporation Device 15da (rev 02) (prog-if 00 [Normal decode]) Physical Slot: 5 Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx+ Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx- Latency: 0 Interrupt: pin A routed to IRQ 200 Bus: primary=57, secondary=58, subordinate=81, sec-latency=0 I/O behind bridge: 00006000-00007fff [size=8K] Memory behind bridge: ac200000-b83fffff [size=194M] Prefetchable memory behind bridge: 00000002b7c00000-00000002d3bfffff [size=448M] Secondary status: 66MHz- FastB2B- ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort- <SERR- <PERR- BridgeCtl: Parity- SERR+ NoISA- VGA- MAbort- >Reset- FastB2B- PriDiscTmr- SecDiscTmr- DiscTmrStat- DiscTmrSERREn- Capabilities: [80] Power Management version 3 Flags: PMEClk- DSI- D1+ D2+ AuxCurrent=375mA PME(D0+,D1+,D2+,D3hot+,D3cold+) Status: D0 NoSoftRst+ PME-Enable- DSel=0 DScale=0 PME- Capabilities: [88] MSI: Enable+ Count=1/1 Maskable- 64bit+ Address: 00000000fee12000 Data: 4026 Capabilities: [ac] Subsystem: Samsung Electronics Co Ltd Device a811 Capabilities: [c0] Express (v2) Upstream Port, MSI 00 DevCap: MaxPayload 128 bytes, PhantFunc 0 ExtTag+ AttnBtn- AttnInd- PwrInd- RBE+ SlotPowerLimit 0.000W DevCtl: Report errors: Correctable- Non-Fatal- Fatal- Unsupported- RlxdOrd+ ExtTag+ PhantFunc- AuxPwr- NoSnoop+ MaxPayload 128 bytes, MaxReadReq 512 bytes DevSta: CorrErr- UncorrErr- FatalErr- UnsuppReq- AuxPwr+ TransPend- LnkCap: Port #0, Speed 2.5GT/s, Width x4, ASPM L0s L1, Exit Latency L0s <2us, L1 <4us ClockPM+ Surprise- LLActRep- BwNot- ASPMOptComp+ LnkCtl: ASPM Disabled; Disabled- CommClk+ ExtSynch- ClockPM- AutWidDis- BWInt- AutBWInt- LnkSta: Speed 2.5GT/s, Width x4, TrErr- Train- SlotClk+ DLActive- BWMgmt- ABWMgmt- DevCap2: Completion Timeout: Not Supported, TimeoutDis-, LTR+, OBFF Not Supported AtomicOpsCap: Routing- DevCtl2: Completion Timeout: 50us to 50ms, TimeoutDis-, LTR+, OBFF Disabled AtomicOpsCtl: EgressBlck- LnkCtl2: Target Link Speed: 2.5GT/s, EnterCompliance- SpeedDis- Transmit Margin: Normal Operating Range, EnterModifiedCompliance- ComplianceSOS- Compliance De-emphasis: -6dB LnkSta2: Current De-emphasis Level: -3.5dB, EqualizationComplete-, EqualizationPhase1- EqualizationPhase2-, EqualizationPhase3-, LinkEqualizationRequest- Capabilities: [100 v1] Device Serial Number 5b-66-34-11-98-c9-a0-00 Capabilities: [200 v1] Advanced Error Reporting UESta: DLP- SDES- TLP- FCP- CmpltTO- CmpltAbrt- UnxCmplt- RxOF- MalfTLP- ECRC- UnsupReq- ACSViol- UEMsk: DLP- SDES- TLP- FCP- CmpltTO- CmpltAbrt- UnxCmplt- RxOF- MalfTLP- ECRC- UnsupReq- ACSViol- UESvrt: DLP+ SDES- TLP- FCP+ CmpltTO- CmpltAbrt- UnxCmplt- RxOF+ MalfTLP+ ECRC- UnsupReq- ACSViol- CESta: RxErr- BadTLP- BadDLLP- Rollover- Timeout- NonFatalErr- CEMsk: RxErr- BadTLP- BadDLLP- Rollover- Timeout- NonFatalErr+ AERCap: First Error Pointer: 00, ECRCGenCap- ECRCGenEn- ECRCChkCap- ECRCChkEn- MultHdrRecCap- MultHdrRecEn- TLPPfxPres- HdrLogCap- HeaderLog: 00000000 00000000 00000000 00000000 Capabilities: [300 v1] Virtual Channel Caps: LPEVC=0 RefClk=100ns PATEntryBits=1 Arb: Fixed- WRR32- WRR64- WRR128- Ctrl: ArbSelect=Fixed Status: InProgress- VC0: Caps: PATOffset=00 MaxTimeSlots=1 RejSnoopTrans- Arb: Fixed+ WRR32- WRR64- WRR128- TWRR128- WRR256- Ctrl: Enable+ ID=0 ArbSelect=Fixed TC/VC=ff Status: NegoPending- InProgress- Capabilities: [400 v1] Power Budgeting <?> Capabilities: [500 v1] Vendor Specific Information: ID=1234 Rev=1 Len=0d8 <?> Capabilities: [600 v1] Latency Tolerance Reporting Max snoop latency: 0ns Max no snoop latency: 0ns Capabilities: [700 v1] #19 Kernel driver in use: pcieport 58:01.0 PCI bridge: Intel Corporation Device 15da (rev 02) (prog-if 00 [Normal decode]) Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx+ Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx- Latency: 0 Interrupt: pin A routed to IRQ 201 Bus: primary=58, secondary=59, subordinate=81, sec-latency=0 I/O behind bridge: 00006000-00007fff [size=8K] Memory behind bridge: ac200000-b83fffff [size=194M] Prefetchable memory behind bridge: 00000002b7c00000-00000002d3bfffff [size=448M] Secondary status: 66MHz- FastB2B- ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort- <SERR- <PERR- BridgeCtl: Parity- SERR+ NoISA- VGA- MAbort- >Reset- FastB2B- PriDiscTmr- SecDiscTmr- DiscTmrStat- DiscTmrSERREn- Capabilities: [80] Power Management version 3 Flags: PMEClk- DSI- D1+ D2+ AuxCurrent=375mA PME(D0+,D1+,D2+,D3hot+,D3cold+) Status: D0 NoSoftRst+ PME-Enable- DSel=0 DScale=0 PME- Capabilities: [88] MSI: Enable+ Count=1/1 Maskable- 64bit+ Address: 00000000fee14000 Data: 4025 Capabilities: [ac] Subsystem: Samsung Electronics Co Ltd Device a811 Capabilities: [c0] Express (v2) Downstream Port (Slot+), MSI 00 DevCap: MaxPayload 128 bytes, PhantFunc 0 ExtTag+ RBE+ DevCtl: Report errors: Correctable- Non-Fatal- Fatal- Unsupported- RlxdOrd+ ExtTag+ PhantFunc- AuxPwr- NoSnoop+ MaxPayload 128 bytes, MaxReadReq 512 bytes DevSta: CorrErr+ UncorrErr- FatalErr- UnsuppReq- AuxPwr+ TransPend- LnkCap: Port #1, Speed 8GT/s, Width x4, ASPM L0s L1, Exit Latency L0s <2us, L1 <4us ClockPM- Surprise- LLActRep+ BwNot+ ASPMOptComp+ LnkCtl: ASPM Disabled; Disabled- CommClk+ ExtSynch- ClockPM- AutWidDis- BWInt- AutBWInt- LnkSta: Speed 8GT/s, Width x4, TrErr- Train- SlotClk+ DLActive+ BWMgmt+ ABWMgmt- SltCap: AttnBtn- PwrCtrl- MRL- AttnInd- PwrInd- HotPlug+ Surprise+ Slot #1, PowerLimit 0.000W; Interlock- NoCompl+ SltCtl: Enable: AttnBtn- PwrFlt- MRL- PresDet+ CmdCplt- HPIrq+ LinkChg+ Control: AttnInd Unknown, PwrInd Unknown, Power- Interlock- SltSta: Status: AttnBtn- PowerFlt- MRL- CmdCplt- PresDet+ Interlock- Changed: MRL- PresDet- LinkState- DevCap2: Completion Timeout: Not Supported, TimeoutDis-, LTR+, OBFF Not Supported ARIFwd- AtomicOpsCap: Routing- DevCtl2: Completion Timeout: 50us to 50ms, TimeoutDis-, LTR+, OBFF Disabled ARIFwd- AtomicOpsCtl: EgressBlck- LnkCtl2: Target Link Speed: 8GT/s, EnterCompliance- SpeedDis-, Selectable De-emphasis: -3.5dB Transmit Margin: Normal Operating Range, EnterModifiedCompliance- ComplianceSOS- Compliance De-emphasis: -6dB LnkSta2: Current De-emphasis Level: -6dB, EqualizationComplete+, EqualizationPhase1+ EqualizationPhase2+, EqualizationPhase3+, LinkEqualizationRequest- Capabilities: [100 v1] Device Serial Number 5b-66-34-11-98-c9-a0-00 Capabilities: [200 v1] Advanced Error Reporting UESta: DLP- SDES- TLP- FCP- CmpltTO- CmpltAbrt- UnxCmplt- RxOF- MalfTLP- ECRC- UnsupReq- ACSViol- UEMsk: DLP- SDES- TLP- FCP- CmpltTO- CmpltAbrt- UnxCmplt- RxOF- MalfTLP- ECRC- UnsupReq- ACSViol- UESvrt: DLP+ SDES- TLP- FCP+ CmpltTO- CmpltAbrt- UnxCmplt- RxOF+ MalfTLP+ ECRC- UnsupReq- ACSViol- CESta: RxErr- BadTLP- BadDLLP+ Rollover- Timeout- NonFatalErr- CEMsk: RxErr- BadTLP- BadDLLP- Rollover- Timeout- NonFatalErr+ AERCap: First Error Pointer: 00, ECRCGenCap- ECRCGenEn- ECRCChkCap- ECRCChkEn- MultHdrRecCap- MultHdrRecEn- TLPPfxPres- HdrLogCap- HeaderLog: 00000000 00000000 00000000 00000000 Capabilities: [300 v1] Virtual Channel Caps: LPEVC=0 RefClk=100ns PATEntryBits=1 Arb: Fixed- WRR32- WRR64- WRR128- Ctrl: ArbSelect=Fixed Status: InProgress- VC0: Caps: PATOffset=00 MaxTimeSlots=1 RejSnoopTrans- Arb: Fixed+ WRR32- WRR64- WRR128- TWRR128- WRR256- Ctrl: Enable+ ID=0 ArbSelect=Fixed TC/VC=ff Status: NegoPending- InProgress- Capabilities: [400 v1] Power Budgeting <?> Capabilities: [500 v1] Vendor Specific Information: ID=1234 Rev=1 Len=0d8 <?> Capabilities: [700 v1] #19 Kernel driver in use: pcieport 59:00.0 Non-Volatile memory controller: Samsung Electronics Co Ltd Device a808 (prog-if 02 [NVM Express]) Subsystem: Samsung Electronics Co Ltd Device a811 Physical Slot: 1 Control: I/O- Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx+ Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx- Latency: 0 Interrupt: pin A routed to IRQ 20 Region 0: Memory at ac200000 (64-bit, non-prefetchable) [size=16K] Capabilities: [40] Power Management version 3 Flags: PMEClk- DSI- D1- D2- AuxCurrent=0mA PME(D0-,D1-,D2-,D3hot-,D3cold-) Status: D0 NoSoftRst+ PME-Enable- DSel=0 DScale=0 PME- Capabilities: [50] MSI: Enable- Count=1/1 Maskable- 64bit+ Address: 0000000000000000 Data: 0000 Capabilities: [70] Express (v2) Endpoint, MSI 00 DevCap: MaxPayload 256 bytes, PhantFunc 0, Latency L0s unlimited, L1 unlimited ExtTag- AttnBtn- AttnInd- PwrInd- RBE+ FLReset+ SlotPowerLimit 0.000W DevCtl: Report errors: Correctable+ Non-Fatal+ Fatal+ Unsupported+ RlxdOrd+ ExtTag- PhantFunc- AuxPwr- NoSnoop+ FLReset- MaxPayload 128 bytes, MaxReadReq 512 bytes DevSta: CorrErr- UncorrErr- FatalErr- UnsuppReq- AuxPwr- TransPend- LnkCap: Port #0, Speed 8GT/s, Width x4, ASPM L1, Exit Latency L1 <64us ClockPM+ Surprise- LLActRep- BwNot- ASPMOptComp+ LnkCtl: ASPM Disabled; RCB 64 bytes Disabled- CommClk+ ExtSynch- ClockPM- AutWidDis- BWInt- AutBWInt- LnkSta: Speed 8GT/s, Width x4, TrErr- Train- SlotClk+ DLActive- BWMgmt- ABWMgmt- DevCap2: Completion Timeout: Range ABCD, TimeoutDis+, LTR+, OBFF Not Supported AtomicOpsCap: 32bit- 64bit- 128bitCAS- DevCtl2: Completion Timeout: 50us to 50ms, TimeoutDis-, LTR+, OBFF Disabled AtomicOpsCtl: ReqEn- LnkCtl2: Target Link Speed: 8GT/s, EnterCompliance- SpeedDis- Transmit Margin: Normal Operating Range, EnterModifiedCompliance- ComplianceSOS- Compliance De-emphasis: -6dB LnkSta2: Current De-emphasis Level: -3.5dB, EqualizationComplete+, EqualizationPhase1+ EqualizationPhase2+, EqualizationPhase3+, LinkEqualizationRequest- Capabilities: [b0] MSI-X: Enable+ Count=33 Masked- Vector table: BAR=0 offset=00003000 PBA: BAR=0 offset=00002000 Capabilities: [100 v2] Advanced Error Reporting UESta: DLP- SDES- TLP- FCP- CmpltTO- CmpltAbrt- UnxCmplt- RxOF- MalfTLP- ECRC- UnsupReq- ACSViol- UEMsk: DLP- SDES- TLP- FCP- CmpltTO- CmpltAbrt- UnxCmplt- RxOF- MalfTLP- ECRC- UnsupReq- ACSViol- UESvrt: DLP+ SDES+ TLP- FCP+ CmpltTO- CmpltAbrt- UnxCmplt- RxOF+ MalfTLP+ ECRC- UnsupReq- ACSViol- CESta: RxErr- BadTLP- BadDLLP- Rollover- Timeout- NonFatalErr- CEMsk: RxErr- BadTLP- BadDLLP- Rollover- Timeout- NonFatalErr+ AERCap: First Error Pointer: 00, ECRCGenCap+ ECRCGenEn- ECRCChkCap+ ECRCChkEn- MultHdrRecCap+ MultHdrRecEn- TLPPfxPres- HdrLogCap- HeaderLog: 00000000 00000000 00000000 00000000 Capabilities: [148 v1] Device Serial Number 00-00-00-00-00-00-00-00 Capabilities: [158 v1] Power Budgeting <?> Capabilities: [168 v1] #19 Capabilities: [188 v1] Latency Tolerance Reporting Max snoop latency: 0ns Max no snoop latency: 0ns Capabilities: [190 v1] L1 PM Substates L1SubCap: PCI-PM_L1.2+ PCI-PM_L1.1+ ASPM_L1.2+ ASPM_L1.1+ L1_PM_Substates+ PortCommonModeRestoreTime=10us PortTPowerOnTime=10us L1SubCtl1: PCI-PM_L1.2- PCI-PM_L1.1- ASPM_L1.2- ASPM_L1.1- T_CommonMode=0us LTR1.2_Threshold=0ns L1SubCtl2: T_PwrOn=10us Kernel driver in use: nvme [3] lspci of the NVME PCI end point in the failure case: localhost ~ # lspci -bvvv -s 59:0.0 59:00.0 Non-Volatile memory controller: Samsung Electronics Co Ltd Device a808 (prog-if 02 [NVM Express]) Subsystem: Samsung Electronics Co Ltd Device a811 Physical Slot: 1 Control: I/O- Mem+ BusMaster- SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx- Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx- Interrupt: pin A routed to IRQ 255 Region 0: Memory at <unassigned> (64-bit, non-prefetchable) <------ BAR is cleared! Capabilities: [40] Power Management version 3 Flags: PMEClk- DSI- D1- D2- AuxCurrent=0mA PME(D0-,D1-,D2-,D3hot-,D3cold-) Status: D0 NoSoftRst+ PME-Enable- DSel=0 DScale=0 PME- Capabilities: [50] MSI: Enable- Count=1/1 Maskable- 64bit+ Address: 0000000000000000 Data: 0000 Capabilities: [70] Express (v2) Endpoint, MSI 00 DevCap: MaxPayload 256 bytes, PhantFunc 0, Latency L0s unlimited, L1 unlimited ExtTag- AttnBtn- AttnInd- PwrInd- RBE+ FLReset+ SlotPowerLimit 0.000W DevCtl: Report errors: Correctable- Non-Fatal- Fatal- Unsupported- RlxdOrd+ ExtTag- PhantFunc- AuxPwr- NoSnoop+ FLReset- MaxPayload 128 bytes, MaxReadReq 512 bytes DevSta: CorrErr+ UncorrErr- FatalErr- UnsuppReq+ AuxPwr- TransPend- LnkCap: Port #0, Speed 8GT/s, Width x4, ASPM L1, Exit Latency L1 <64us ClockPM+ Surprise- LLActRep- BwNot- ASPMOptComp+ LnkCtl: ASPM Disabled; RCB 64 bytes Disabled- CommClk+ ExtSynch- ClockPM- AutWidDis- BWInt- AutBWInt- LnkSta: Speed 8GT/s, Width x4, TrErr- Train- SlotClk+ DLActive- BWMgmt- ABWMgmt- DevCap2: Completion Timeout: Range ABCD, TimeoutDis+, LTR+, OBFF Not Supported DevCtl2: Completion Timeout: 50us to 50ms, TimeoutDis-, LTR+, OBFF Disabled AtomicOpsCtl: ReqEn- LnkCtl2: Target Link Speed: 8GT/s, EnterCompliance- SpeedDis- Transmit Margin: Normal Operating Range, EnterModifiedCompliance- ComplianceSOS- Compliance De-emphasis: -6dB LnkSta2: Current De-emphasis Level: -3.5dB, EqualizationComplete+, EqualizationPhase1+ EqualizationPhase2+, EqualizationPhase3+, LinkEqualizationRequest- Capabilities: [b0] MSI-X: Enable- Count=33 Masked- Vector table: BAR=0 offset=00003000 PBA: BAR=0 offset=00002000 Capabilities: [100 v2] Advanced Error Reporting UESta: DLP- SDES- TLP- FCP- CmpltTO- CmpltAbrt- UnxCmplt- RxOF- MalfTLP- ECRC- UnsupReq- ACSViol- UEMsk: DLP- SDES- TLP- FCP- CmpltTO- CmpltAbrt- UnxCmplt- RxOF- MalfTLP- ECRC- UnsupReq- ACSViol- UESvrt: DLP+ SDES+ TLP- FCP+ CmpltTO- CmpltAbrt- UnxCmplt- RxOF+ MalfTLP+ ECRC- UnsupReq- ACSViol- CESta: RxErr- BadTLP- BadDLLP- Rollover- Timeout- NonFatalErr- CEMsk: RxErr- BadTLP- BadDLLP- Rollover- Timeout- NonFatalErr+ AERCap: First Error Pointer: 00, ECRCGenCap+ ECRCGenEn- ECRCChkCap+ ECRCChkEn- MultHdrRecCap+ MultHdrRecEn- TLPPfxPres- HdrLogCap- HeaderLog: 00000000 00000000 00000000 00000000 Capabilities: [148 v1] Device Serial Number 00-00-00-00-00-00-00-00 Capabilities: [158 v1] Power Budgeting <?> Capabilities: [168 v1] #19 Capabilities: [188 v1] Latency Tolerance Reporting Max snoop latency: 0ns Max no snoop latency: 0ns Capabilities: [190 v1] L1 PM Substates L1SubCap: PCI-PM_L1.2+ PCI-PM_L1.1+ ASPM_L1.2+ ASPM_L1.1+ L1_PM_Substates+ PortCommonModeRestoreTime=10us PortTPowerOnTime=10us L1SubCtl1: PCI-PM_L1.2- PCI-PM_L1.1- ASPM_L1.2- ASPM_L1.1- T_CommonMode=0us LTR1.2_Threshold=0ns L1SubCtl2: T_PwrOn=10us