Yes, offset cancellation may fail on Stratix® IV GX or GT devices under the following conditions.
- Quartus® II Software Versions 11.0SP1 and earlier is used to compile the design.
- EyeQ and/or DFE is switched on in the ALTGX_RECONFIG MegaWizard™.
- The ALTGX_RECONFIG MegaWizard controls more than four transceiver channels.
The effect of a failed offset cancellation process may be an increase in bit error rate (BER) for an already marginal transceiver link. Transceiver links with sufficient margin will likely not be affected.
You can workaround this issue by instantiating one ALTGX_RECONFIG controller MegaWizard per transceiver block.
This issue will be fixed in a future version of the Quartus II Software