X550-T2 only works PCIe Gen2 x4

[Yuwei1]

Hi

I have X550-T2 dual ports NIC with production label date : 2816CR (28 week 2016)

And I installed it on Ubuntu 22.04 and already update to last driver 5.19.9 and firmware 3.60.

however, I found the PCIe always works with PCIe Gen2 width x4. And I check the Intel product page it mention X550-T2 was PCIe Gen3 x4

then I check the lspci for more information about NIC:

# lspci -vv -s 01:00.0
01:00.0 Ethernet controller: Intel Corporation Ethernet Controller 10G X550T (rev 01)
Subsystem: Intel Corporation Ethernet Converged Network Adapter X550-T2
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 16
IOMMU group: 2
Region 0: Memory at 6000400000 (64-bit, prefetchable) [size=4M]
Region 4: Memory at 6000804000 (64-bit, prefetchable) [size=16K]
Expansion ROM at 90000000 [disabled] [size=512K]
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=1 PME-
Capabilities: [50] MSI: Enable- Count=1/1 Maskable+ 64bit+
Address: 0000000000000000 Data: 0000
Masking: 00000000 Pending: 00000000
Capabilities: [70] MSI-X: Enable+ Count=64 Masked-
Vector table: BAR=4 offset=00000000
PBA: BAR=4 offset=00002000
Capabilities: [a0] Express (v1) Endpoint, MSI 00
DevCap: MaxPayload 512 bytes, PhantFunc 0, Latency L0s <512ns, L1 <64us
ExtTag- AttnBtn- AttnInd- PwrInd- RBE+ FLReset+ SlotPowerLimit 0.000W
DevCtl: CorrErr+ NonFatalErr+ FatalErr+ UnsupReq+
RlxdOrd+ ExtTag- PhantFunc- AuxPwr- NoSnoop- FLReset-
MaxPayload 256 bytes, MaxReadReq 512 bytes
DevSta: CorrErr+ NonFatalErr- FatalErr- UnsupReq+ AuxPwr- TransPend-
LnkCap: Port #0, Speed 5GT/s, Width x8, ASPM not supported
ClockPM- Surprise- LLActRep- BwNot- ASPMOptComp+
LnkCtl: ASPM Disabled; RCB 64 bytes, Disabled- CommClk+
ExtSynch- ClockPM- AutWidDis- BWInt- AutBWInt-
LnkSta: Speed 5GT/s (ok), Width x4 (downgraded)
TrErr- Train- SlotClk+ DLActive- BWMgmt- ABWMgmt-
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: [140 v1] Device Serial Number 00-00-c9-ff-ff-00-00-00
Capabilities: [150 v1] Alternative Routing-ID Interpretation (ARI)
ARICap: MFVC- ACS-, Next Function: 1
ARICtl: MFVC- ACS-, Function Group: 0
Capabilities: [160 v1] Single Root I/O Virtualization (SR-IOV)
IOVCap: Migration-, Interrupt Message Number: 000
IOVCtl: Enable- Migration- Interrupt- MSE- ARIHierarchy-
IOVSta: Migration-
Initial VFs: 64, Total VFs: 64, Number of VFs: 0, Function Dependency Link: 00
VF offset: 384, stride: 2, Device ID: 1565
Supported Page Size: 00000553, System Page Size: 00000001
Region 0: Memory at 0000000090100000 (64-bit, non-prefetchable)
Region 3: Memory at 0000000090200000 (64-bit, non-prefetchable)
VF Migration: offset: 00000000, BIR: 0
Capabilities: [1a0 v1] Transaction Processing Hints
No steering table available
Capabilities: [1b0 v1] Access Control Services
ACSCap: SrcValid- TransBlk- ReqRedir- CmpltRedir- UpstreamFwd- EgressCtrl- DirectTrans-
ACSCtl: SrcValid- TransBlk- ReqRedir- CmpltRedir- UpstreamFwd- EgressCtrl- DirectTrans-
Capabilities: [1c0 v1] Latency Tolerance Reporting
Max snoop latency: 71680ns
Max no snoop latency: 71680ns
Kernel driver in use: ixgbe
Kernel modules: ixgbe

the strange thing was it capability showed:

> LnkCap: Port #0, Speed 5GT/s, Width x8, ASPM not supported

it means NIC consider itself was "Width x8" in PCIe Gen2 ??? But the hardware of this NIC has only Width x4

From the data sheet, it seems there X550-AT2 and X550-BT2 :
25 mm x 25 mm (X550-BT2)
17 mm x 17 mm (X550-AT2)

Then I checked the chipset of my NIC, the size seems to "BT2" and according to
Table 1-2. Host Interface Features it mentioned "or X550-BT2, x8 available in Gen 1/2 only"

Did X550-T2 has various revision with different HW capability? Or any configuration setting will limit this HW capability? And Why My NIC was only has x4 HW and used X550-BT2?

[Sazirah]

Hi Yuwei1,

Thank you for posting in Intel Ethernet Communities.

Regarding your enquiry above, please give me some time to check from my end. I will revert to you here as soon as possible.

Regards,

Sazzy_Intel

[Sazirah]

Hi Yuwei1,

Good day.

My apologies for taking some time to revert here. 

Please refer below for your enquiries:

1) it means NIC consider itself was "Width x8" in PCIe Gen2 ??? But the hardware of this NIC has only Width x4    

This product supports x4 lane PCIe, however it is operable in x8 and x16 slots. 

You can refer here under Product Brief documentation: https://ark.intel.com/content/www/us/en/ark/products/88209/intel-ethernet-converged-network-adapter-x550-t2.html

2) From the data sheet, it seems there X550-AT2 and X550-BT2 :

25 mm x 25 mm (X550-BT2)

17 mm x 17 mm (X550-AT2)

Then I checked the chipset of my NIC, the size seems to "BT2" and according to

Table 1-2. Host Interface Features it mentioned "or X550-BT2, x8 available in Gen 1/2 only"  

                                                                                                                                                                        Yes, you are correct. Intel X550-T2 comes in two package sizes and yours is X550-AT2. Hardware default is the x4 link for X550-AT2 (you may refer to the datasheet page 76). The x8 width is available only in the X550-BT2 as it does not support Gen3 link speed (8GT/s). For your information, X550-AT2 classifies as Gen3 because it support 8.0GT/s.

I hope this clarifies your enquiries.

Regards,

Sazzy_Intel

[Sazirah]

Hi Yuwei1,

Good day,

This is related to your enquiries above, I would like to check if the issue has resolved?

If you have any questions or clarifications, please let me know.

Regards,

Sazzy_Intel

[Sazirah]

Hi Yuwei1,

Good day

This is regarding your enquiries above. Since we have not seen an update, if you need any additional information, please submit a new question as this thread will no longer be monitored.

Best Regards,

Sazzy_Intel