On Fri, Apr 16, 2021 at 07:31:19PM +0200, Pali Rohár wrote: > Hello! I'm getting following error line in dmesg for NVMe disk with > v5.12-rc7 kernel version: > > [ 3.226462] pci 0000:04:00.0: can't set Max Payload Size to 256; if necessary, use "pci=pcie_bus_safe" and report a bug > > lspci output for this NVMe disk is: > > 04:00.0 Non-Volatile memory controller [0108]: Silicon Motion, Inc. Device [126f:2263] (rev 03) (prog-if 02 [NVM Express]) > Subsystem: Silicon Motion, Inc. Device [126f:2263] > 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 55 > Region 0: Memory at e8000000 (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=1/8 Maskable+ 64bit+ > Address: 0000000000000000 Data: 0000 > Masking: 00000000 Pending: 00000000 > Capabilities: [70] Express (v2) Endpoint, MSI 00 > DevCap: MaxPayload 128 bytes, PhantFunc 0, Latency L0s unlimited, L1 unlimited > ExtTag- AttnBtn- AttnInd- PwrInd- RBE+ FLReset+ SlotPowerLimit 26.000W > DevCtl: CorrErr+ NonFatalErr+ FatalErr+ UnsupReq+ > RlxdOrd+ ExtTag- PhantFunc- AuxPwr- NoSnoop- FLReset- > MaxPayload 128 bytes, MaxReadReq 512 bytes > DevSta: CorrErr- NonFatalErr- FatalErr- UnsupReq- AuxPwr+ TransPend- > LnkCap: Port #0, Speed 8GT/s, Width x4, ASPM not supported > ClockPM+ Surprise- LLActRep- BwNot- ASPMOptComp+ > LnkCtl: ASPM Disabled; RCB 64 bytes, Disabled- CommClk- > ExtSynch- ClockPM- AutWidDis- BWInt- AutBWInt- > LnkSta: Speed 2.5GT/s (downgraded), Width x1 (downgraded) > TrErr- Train- SlotClk+ DLActive- BWMgmt- ABWMgmt- > DevCap2: Completion Timeout: Range ABCD, TimeoutDis+ NROPrPrP- LTR+ > 10BitTagComp- 10BitTagReq- OBFF Not Supported, ExtFmt- EETLPPrefix- > EmergencyPowerReduction Not Supported, EmergencyPowerReductionInit- > FRS- TPHComp- ExtTPHComp- > AtomicOpsCap: 32bit- 64bit- 128bitCAS- > DevCtl2: Completion Timeout: 50us to 50ms, TimeoutDis- LTR- 10BitTagReq- OBFF Disabled, > AtomicOpsCtl: ReqEn- > LnkCap2: Supported Link Speeds: 2.5-8GT/s, Crosslink- Retimer- 2Retimers- DRS- > 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- > Retimer- 2Retimers- CrosslinkRes: unsupported > Capabilities: [b0] MSI-X: Enable+ Count=16 Masked- > Vector table: BAR=0 offset=00002000 > PBA: BAR=0 offset=00002100 > 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- AdvNonFatalErr- > CEMsk: RxErr- BadTLP- BadDLLP- Rollover- Timeout- AdvNonFatalErr+ > AERCap: First Error Pointer: 00, ECRCGenCap+ ECRCGenEn- ECRCChkCap+ ECRCChkEn- > MultHdrRecCap- MultHdrRecEn- TLPPfxPres- HdrLogCap- > HeaderLog: 00000000 00000000 00000000 00000000 > Capabilities: [158 v1] Secondary PCI Express > LnkCtl3: LnkEquIntrruptEn- PerformEqu- > LaneErrStat: 0 > Capabilities: [178 v1] Latency Tolerance Reporting > Max snoop latency: 0ns > Max no snoop latency: 0ns > Capabilities: [180 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 > L1SubCtl2: T_PwrOn=10us > Kernel driver in use: nvme > > And I cannot understand. Why is kernel trying to set Max Payload Size to > 256 bytes when NVMe disk in Device Capabilities register presents that > supports Maximal Payload size only 128 bytes? The error indicates that the port your nvme pcie device is connected is not reporting a matching MPS. The kernel will attempt to tune the port if it's a RP so they match. If you see this error, that means the RP setting wasn't successful. If the SSD is connected to a bridge, you'll need to use the kernel parameter to force retuning the bus.
