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From: Bjorn Helgaas <helgaas@kernel.org>
To: Billy Araujo <billyaraujo@gmail.com>
Cc: linux-pci@vger.kernel.org, Kishon Vijay Abraham I <kishon@ti.com>,
	linux-omap@vger.kernel.org
Subject: Re: PCI IRQ assignment broken from 4.9 onwards (swizzle?)
Date: Thu, 8 Oct 2020 10:38:09 -0500	[thread overview]
Message-ID: <20201008153809.GA3327800@bjorn-Precision-5520> (raw)
In-Reply-To: <CAEt4U6Xqo8GU6VtBi86iK2-Q3usyHazoASdj1qb_BK-_Gso2kA@mail.gmail.com>

On Thu, Oct 08, 2020 at 09:39:23AM +0100, Billy Araujo wrote:
> Hi Bjorn,
> 
> Thanks for your answer. Yes, that would be my next step.
> I am also hoping the latest kernel doesn't have this issue because
> that would mean I would be stuck with version 4.9.
> Also I could discover from which patch this stopped working but that
> would be very time consuming. If I was to add some debug prints where
> should I start? Would this be done in setup-irq.c?
> In other words, is "pci_assign_irq" function responsible for all irq
> assignments?

Start by testing the latest kernel.  Don't bother trying to debug it
from first principles until you know whether somebody has already
fixed it.

> On Wed, Oct 7, 2020 at 5:41 PM Bjorn Helgaas <helgaas@kernel.org> wrote:
> >
> > [+cc Kishon, linux-omap (maybe this is dra7xx-related?)]
> >
> > On Wed, Oct 07, 2020 at 10:56:33AM +0100, Billy Araujo wrote:
> > > 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.
> >
> > Sorry for the issue, and thanks very much for the report.  Is it
> > possible to test a current kernel, e.g., v5.8 or v5.9-rc8?
> >
> > My guess is this is related to the PCI controller driver; would that
> > be pci-dra7xx.c?
> >
> > > 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]

      reply	other threads:[~2020-10-08 15:38 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-07  9:56 PCI IRQ assignment broken from 4.9 onwards (swizzle?) Billy Araujo
2020-10-07 16:41 ` Bjorn Helgaas
2020-10-08  8:39   ` Billy Araujo
2020-10-08 15:38     ` Bjorn Helgaas [this message]

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