Hi, I have been testing a TI AM57xx board and a NXP iMX8 board with a GPIB PCIe card. TI board (Phytec): https://www.phytec.com/product/phycore-am57x/ NXP board (Variscite): https://www.variscite.com/product/system-on-module-som/cortex-a53-krait/var-som-mx8m-mini-nxp-i-mx8m-mini/ The GPIB PCIe card has a Texas Instruments XIO2000(A)/XIO2200A PCI Express-to-PCI Bridge. Issue: I have noticed is that on Linux kernel 4.9, the Linux PCI driver assigns correctly an IRQ number: Linux am5728-phycore-rdk 4.9.41-ga962b18-BSP-Yocto-TISDK-AM57xx-PD18.1.0 02:00.0 Communication controller: National Instruments PCIe-GPIB (rev 02) Subsystem: National Instruments PCIe-GPIB Control: I/O- Mem- BusMaster- SpecCycle- MemWINV- VGASnoop- ParErr+ Stepping- SERR+ FastB2B- DisINTx- Status: Cap- 66MHz- UDF- FastB2B+ ParErr- DEVSEL=medium >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx- Interrupt: pin A routed to IRQ 470 On a newer kernel (this case 4.19), PCI driver doesn't assign an IRQ number. Linux am57xx-phycore-kit 4.19.79-g35d36cd54d #1 SMP PREEMPT Wed Sep 30 14:04:18 UTC 2020 armv7l GNU/Linux 02:00.0 Communication controller: National Instruments PCIe-GPIB (rev 02) Subsystem: National Instruments PCIe-GPIB Control: I/O- Mem- BusMaster- SpecCycle- MemWINV- VGASnoop- ParErr+ Stepping- SERR+ FastB2B- DisINTx- Status: Cap- 66MHz- UDF- FastB2B+ ParErr- DEVSEL=medium >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx- Interrupt: pin A routed to IRQ 0 Same issue happened on the NXP board, so it seems Linux related. I have tested kernels 4.14, 4.19 and 5.4.3. The IRQ is important to get the legacy interrupts working. Looking at the code there has been some refactoring of how PCI assigns IRQ number when there is a chain of bridges. I am not too familiar with how the code works but I wonder if this has affected how the PCI assignment works. Looking in setup-irq.c: /* If this device is not on the primary bus, we need to figure out which interrupt pin it will come in on. We know which slot it will come in on 'cos that slot is where the bridge is. Each time the interrupt line passes through a PCI-PCI bridge we must apply the swizzle function. */ Line 44: if (hbrg->swizzle_irq) >From my understanding, this "if" didn't exist in Linux kernel 4.9. If swizzle function isn't assigned in the newer kernels it just stays as 0. This might be completely unrelated as I said I have no understanding how this code is supposed to work. What I ask is if anyone has experienced any issues similar to this in these more recent kernel versions. Regards, Billy. Debug output with the issue: root@am57xx-phycore-kit:~# uname -a Linux am57xx-phycore-kit 4.19.79-g35d36cd54d #1 SMP PREEMPT Wed Sep 30 14:04:18 UTC 2020 armv7l GNU/Linux root@am57xx-phycore-kit:~# lspci -vv 00:00.0 PCI bridge: Texas Instruments Multicore DSP+ARM KeyStone II SOC (rev 01) (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 A routed to IRQ 180 Region 0: Memory at 20100000 (64-bit, non-prefetchable) [size=1M] Bus: primary=00, secondary=01, subordinate=ff, sec-latency=0 I/O behind bridge: None Memory behind bridge: 20200000-202fffff [size=1M] Prefetchable memory behind bridge: None Secondary status: 66MHz- FastB2B- ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort+ <SERR- <PERR- BridgeCtl: Parity+ SERR- NoISA- VGA- VGA16- MAbort- >Reset- FastB2B- PriDiscTmr- SecDiscTmr- DiscTmrStat- DiscTmrSERREn- 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: 00000000ae15b000 Data: 0000 Capabilities: [70] Express (v2) Root Port (Slot-), MSI 00 DevCap: MaxPayload 256 bytes, PhantFunc 0 ExtTag- RBE+ DevCtl: CorrErr+ NonFatalErr+ FatalErr+ UnsupReq+ RlxdOrd+ ExtTag- PhantFunc- AuxPwr- NoSnoop+ MaxPayload 128 bytes, MaxReadReq 512 bytes DevSta: CorrErr- NonFatalErr- FatalErr- UnsupReq- AuxPwr- TransPend- LnkCap: Port #0, Speed 5GT/s, Width x2, ASPM L0s L1, Exit Latency L0s <512ns, L1 <64us ClockPM- Surprise- LLActRep+ BwNot+ ASPMOptComp+ LnkCtl: ASPM Disabled; RCB 128 bytes Disabled- CommClk- ExtSynch- ClockPM- AutWidDis- BWInt- AutBWInt- LnkSta: Speed 2.5GT/s (downgraded), Width x1 (downgraded) TrErr- Train- SlotClk+ DLActive+ BWMgmt- ABWMgmt- RootCtl: ErrCorrectable- ErrNon-Fatal- ErrFatal- PMEIntEna+ CRSVisible- RootCap: CRSVisible- RootSta: PME ReqID 0000, PMEStatus- PMEPending- DevCap2: Completion Timeout: Range ABCD, TimeoutDis+, LTR-, OBFF Not Supported ARIFwd- AtomicOpsCap: Routing- 32bit- 64bit- 128bitCAS- DevCtl2: Completion Timeout: 50us to 50ms, TimeoutDis-, LTR-, OBFF Disabled ARIFwd- AtomicOpsCtl: ReqEn- EgressBlck- LnkCtl2: Target Link Speed: 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 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 RootCmd: CERptEn+ NFERptEn+ FERptEn+ RootSta: CERcvd- MultCERcvd- UERcvd- MultUERcvd- FirstFatal- NonFatalMsg- FatalMsg- IntMsg 0 ErrorSrc: ERR_COR: 0000 ERR_FATAL/NONFATAL: 0000 Kernel driver in use: pcieport 01:00.0 PCI bridge: Texas Instruments XIO2000(A)/XIO2200A PCI Express-to-PCI Bridge (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- Bus: primary=01, secondary=02, subordinate=02, sec-latency=0 I/O behind bridge: None Memory behind bridge: 20200000-202fffff [size=1M] Prefetchable memory behind bridge: None Secondary status: 66MHz- FastB2B+ ParErr- DEVSEL=medium >TAbort- <TAbort- <MAbort+ <SERR- <PERR- BridgeCtl: Parity+ SERR- NoISA- VGA- VGA16- MAbort+ >Reset- FastB2B+ PriDiscTmr- SecDiscTmr- DiscTmrStat- DiscTmrSERREn- Capabilities: [50] Power Management version 2 Flags: PMEClk- DSI- D1+ D2+ AuxCurrent=0mA PME(D0-,D1-,D2-,D3hot-,D3cold-) Status: D0 NoSoftRst- PME-Enable- DSel=0 DScale=0 PME- Bridge: PM- B3+ Capabilities: [60] MSI: Enable- Count=1/16 Maskable- 64bit+ Address: 0000000000000000 Data: 0000 Capabilities: [80] Subsystem: Device 0000:0000 Capabilities: [90] Express (v1) PCI-Express to PCI/PCI-X Bridge, MSI 00 DevCap: MaxPayload 512 bytes, PhantFunc 0 ExtTag- AttnBtn- AttnInd- PwrInd- RBE- SlotPowerLimit 0.000W DevCtl: CorrErr- NonFatalErr- FatalErr- UnsupReq- RlxdOrd- ExtTag- PhantFunc- AuxPwr- NoSnoop+ BrConfRtry- MaxPayload 128 bytes, MaxReadReq 512 bytes DevSta: CorrErr- NonFatalErr+ FatalErr- UnsupReq- AuxPwr- TransPend- LnkCap: Port #0, Speed 2.5GT/s, Width x1, ASPM L0s L1, Exit Latency L0s <1us, L1 <16us ClockPM- Surprise- LLActRep- BwNot- ASPMOptComp- LnkCtl: ASPM Disabled; RCB 64 bytes Disabled- CommClk- ExtSynch- ClockPM- AutWidDis- BWInt- AutBWInt- LnkSta: Speed 2.5GT/s (ok), Width x1 (ok) TrErr- Train- SlotClk+ DLActive- BWMgmt- ABWMgmt- 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- 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 02:00.0 Communication controller: National Instruments PCIe-GPIB (rev 02) Subsystem: National Instruments PCIe-GPIB Control: I/O- Mem- BusMaster- SpecCycle- MemWINV- VGASnoop- ParErr+ Stepping- SERR+ FastB2B- DisINTx- Status: Cap- 66MHz- UDF- FastB2B+ ParErr- DEVSEL=medium >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx- Interrupt: pin A routed to IRQ 0 Region 0: Memory at 20204000 (32-bit, non-prefetchable) [disabled] [size=2K] Region 1: Memory at 20200000 (32-bit, non-prefetchable) [disabled] [size=16K]
