Visible to Intel only — GUID: nzy1622063904739
Ixiasoft
Visible to Intel only — GUID: nzy1622063904739
Ixiasoft
2.3.8. Unsuccessful TX Equalization
Description
In the P-Tile Intel FPGA IP for PCIe* , when a speed change to Gen3/Gen4 speed is attempted for the first time with full TxEq enabled, if all phases of equalization do not successfully complete, the link reverts back to the lowest speed that passed equalization. The Equalization results for Gen3 and Gen4 are recorded in the following registers.
- For Gen3: Link Status 2 Register [4:1]:
- [1] Equalization 8.0 GT/s Complete
- [2] Equalization 8.0 GT/s Phase 1 Successful
- [3] Equalization 8.0 GT/s Phase 2 Successful
- [4] Equalization 8.0 GT/s Phase 3 Successful
- For Gen4: 16.0 GT/s Status Register [3:0]:
- [0] Equalization 16.0 GT/s Complete
- [1] Equalization 16.0 GT/s Phase 1 Successful
- [2] Equalization 16.0 GT/s Phase 2 Successful
- [3] Equalization 16.0 GT/s Phase 3 Successful
If equalization is attempted, the “Complete” bit is set for that speed regardless if the other phases of equalization completed successfully. Once the “Complete” bit is set, the P-Tile permits a speed change by setting the Target Link Speed in the Link Control 2 Register. As a result, the link may train to Gen3/Gen4 speeds with sub-optimal transmitter equalization settings.
- For Gen3: Link Status 2 Register [4:1]
- For Gen4: 16.0 GT/s Status Register [3:0]
To re-initiate the equalization procedure, write 1b to the Perform Equalization bit [0] in the Link Control 3 register.
Workaround
None.
Status
- Intel® Stratix® 10 DX 2800
- Intel® Stratix® 10 DX 2100
- Intel® Stratix® 10 DX 1100
Status: No planned fix.