Re: [PATCH V6 02/15] PCI/PME: Export pcie_pme_disable_msi() & pcie_pme_no_msi() APIs

From: Vidya Sagar
Date: Fri May 17 2019 - 22:01:32 EST


On 5/18/2019 12:25 AM, Bjorn Helgaas wrote:
On Fri, May 17, 2019 at 11:23:36PM +0530, Vidya Sagar wrote:
On 5/17/2019 6:54 PM, Bjorn Helgaas wrote:
Do you have "lspci -vvxxx" output for the root ports handy?

If there's some clue in the standard config space that would tell us
that MSI works for some events but not others, we could make the PCI
core pay attention it. That would be the best solution because it
wouldn't require Tegra-specific code.

Here is the output of 'lspci vvxxx' for one of Tegra194's root ports.

Thanks!

This port advertises both MSI and MSI-X, and neither one is enabled.
This particular port doesn't have a slot, so hotplug isn't applicable
to it.

But if I understand correctly, if MSI or MSI-X were enabled and the
port had a slot, the port would generate MSI/MSI-X hotplug interrupts.
But PME and AER events would still cause INTx interrupts (even with
MSI or MSI-X enabled).

Do I have that right? I just want to make sure that the reason for
PME being INTx is a permanent hardware choice and that it's not
related to MSI and MSI-X currently being disabled.
Yes. Thats right. Its hardware choice that our hardware engineers made to
use INTx for PME instead of MSI irrespective of MSI/MSI-X enabled/disabled
in the root port.


0005:00:00.0 PCI bridge: NVIDIA Corporation Device 1ad0 (rev a1) (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 50
Bus: primary=00, secondary=01, subordinate=ff, sec-latency=0
I/O behind bridge: None
Memory behind bridge: 40000000-400fffff [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=375mA 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
Masking: 00000000 Pending: 00000000
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 16GT/s, Width x8, ASPM L0s L1, Exit Latency L0s <1us, L1 <64us
ClockPM- Surprise+ LLActRep+ BwNot+ ASPMOptComp+
LnkCtl: ASPM Disabled; RCB 64 bytes Disabled- CommClk+
ExtSynch- ClockPM- AutWidDis- BWInt+ AutBWInt-
LnkSta: Speed 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: 16GT/s, EnterCompliance- SpeedDis-
Transmit Margin: Normal Operating Range, EnterModifiedCompliance- ComplianceSOS-
Compliance De-emphasis: -6dB
LnkSta2: Current De-emphasis Level: -6dB, EqualizationComplete-, EqualizationPhase1-
EqualizationPhase2-, EqualizationPhase3-, LinkEqualizationRequest-
Capabilities: [b0] MSI-X: Enable- Count=8 Masked-
Vector table: BAR=2 offset=00000000
PBA: BAR=2 offset=00010000
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
Capabilities: [148 v1] Secondary PCI Express <?>
Capabilities: [168 v1] Physical Layer 16.0 GT/s <?>
Capabilities: [190 v1] Lane Margining at the Receiver <?>
Capabilities: [1c0 v1] L1 PM Substates
L1SubCap: PCI-PM_L1.2+ PCI-PM_L1.1+ ASPM_L1.2+ ASPM_L1.1+ L1_PM_Substates+
PortCommonModeRestoreTime=60us PortTPowerOnTime=40us
L1SubCtl1: PCI-PM_L1.2- PCI-PM_L1.1- ASPM_L1.2- ASPM_L1.1-
T_CommonMode=10us LTR1.2_Threshold=0ns
L1SubCtl2: T_PwrOn=10us
Capabilities: [1d0 v1] Vendor Specific Information: ID=0002 Rev=4 Len=100 <?>
Capabilities: [2d0 v1] Vendor Specific Information: ID=0001 Rev=1 Len=038 <?>
Capabilities: [308 v1] Data Link Feature <?>
Capabilities: [314 v1] Precision Time Measurement
PTMCap: Requester:+ Responder:+ Root:+
PTMClockGranularity: 16ns
PTMControl: Enabled:- RootSelected:-
PTMEffectiveGranularity: Unknown
Capabilities: [320 v1] Vendor Specific Information: ID=0004 Rev=1 Len=054 <?>
Kernel driver in use: pcieport
00: de 10 d0 1a 07 01 10 00 a1 00 04 06 00 00 01 00
10: 00 00 00 00 00 00 00 00 00 01 ff 00 f0 00 00 00
20: 00 40 00 40 f1 ff 01 00 00 00 00 00 00 00 00 00
30: 00 00 00 00 40 00 00 00 00 00 00 00 32 01 02 00
40: 01 50 c3 c9 08 00 00 00 00 00 00 00 00 00 00 00
50: 05 70 80 01 00 00 00 00 00 00 00 00 00 00 00 00
60: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
70: 10 b0 42 00 01 80 00 00 1f 28 10 00 84 4c 7b 00
80: 40 04 12 f0 00 00 00 00 c0 03 40 00 18 00 01 00
90: 00 00 00 00 1f 0c 01 00 00 04 00 00 1e 00 80 01
a0: 04 00 00 02 00 00 00 00 00 00 00 00 00 00 00 00
b0: 11 00 07 00 02 00 00 00 02 00 01 00 00 00 00 00
c0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
e0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
f0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00