AR# 33710

Design Advisory for the Endpoint Block Plus Wrapper v1.12 for PCI Express - Extended deassertions of trn_rnp_ok_n could result in completions being blocked inside the core

Description

Known Issue: 1.12, v1.11, v1.10.1, v1.10, v1.9.4, v1.9.3, v1.9.2, v1.9.1, v1.9, v1.8, v1.7.1. v1.6, v1.5, v1.4, v1.3, v1.2, v1.1

By deasserting trn_rnp_ok_n, the user application instructs the wrapper to not send Non-Posted packets to the user. Posted and Completions packets should bypass the stalled Non-posted packets and be sent to the user application. A problem exists where if trn_rnp_ok_n is deasserted for such a period of time that the wrappers bypass packet queue fills with non-posted packets, the wrapper is no longer able to drain completion packets from the block if another non-posted packet is waiting in the integrated blocks receive buffer ahead of the completion packet.

Solution

This problem is rare and would only occur if trn_rnp_ok_n is deasserted for a long enough time that the block receives numerous non-posted packets. More than 8 non-posted packets would have to be received while trn_rnp_ok_n is deasserted for this problem to occur.

This problem is fixed in v1.13 of the core and above.

Revision History
07/13/2011 - Updated that fix is available in v1.13 of core
07/05/2011 - Updated title
10/26/2009 - Initial release

Linked Answer Records

Master Answer Records

Answer Number Answer Title Version Found Version Resolved
33580 Design Advisory for the Virtex-5 FPGA Endpoint Block Plus Wrapper for PCI Express Master Answer Record N/A N/A

Associated Answer Records

Answer Number Answer Title Version Found Version Resolved
33580 Design Advisory for the Virtex-5 FPGA Endpoint Block Plus Wrapper for PCI Express Master Answer Record N/A N/A
AR# 33710
Date 08/26/2013
Status Active
Type Design Advisory
IP