11.1 Known Issue - Timing - There are inconsistencies with the timing report; incorrectly reports failing paths

Description

There are inconsistencies with the timing report where it incorrectly reports failing paths.

In the start of the timing report, the following incorrect timing errors appear: 

================================================================================ 

Timing constraint: TIMEGRP "IN_GMII" OFFSET = IN 2 ns VALID 2 ns BEFORE COMP  

"gmii_tx_clk"; 

10 paths analyzed, 10 endpoints analyzed, 10 failing endpoints 

20 timing errors detected. (10 setup errors, 10 hold errors) 

Minimum allowable offset is 2.069ns. 

---------------------------------------------------------------------------------------------------------------------- 

Then, at the end of the report (in the details), there are no timing failures: 

TIMEGRP "IN_GMII" OFFSET = IN 2 ns VALID 2 ns BEFORE COMP "gmii_tx_clk"; 

Worst Case Data Window 0.944; Ideal Clock Offset To Actual Clock -0.154;  

------------------+------------+------------+---------+---------+-------------+ 

| | | Setup | Hold |Source Offset| 

Source | Setup | Hold | Slack | Slack | To Center | 

------------------+------------+------------+---------+---------+-------------+ 

gmii_tx_en | 1.271(R)| -0.386(R)| 0.729| 0.386| 0.171| 

gmii_tx_er | 1.307(R)| -0.413(R)| 0.693| 0.413| 0.140| 

gmii_txd<0> | 1.291(R)| -0.400(R)| 0.709| 0.400| 0.154| 

gmii_txd<1> | 1.318(R)| -0.426(R)| 0.682| 0.426| 0.128| 

gmii_txd<2> | 1.281(R)| -0.391(R)| 0.719| 0.391| 0.164| 

gmii_txd<3> | 1.305(R)| -0.415(R)| 0.695| 0.415| 0.140| 

gmii_txd<4> | 1.268(R)| -0.378(R)| 0.732| 0.378| 0.177| 

gmii_txd<5> | 1.283(R)| -0.393(R)| 0.717| 0.393| 0.162| 

gmii_txd<6> | 1.261(R)| -0.374(R)| 0.739| 0.374| 0.183| 

gmii_txd<7> | 1.263(R)| -0.379(R)| 0.737| 0.379| 0.179| 

------------------+------------+------------+---------+---------+-------------+ 

Worst Case Summary| 1.318| -0.374| 0.682| 0.374| | 

------------------+------------+------------+---------+---------+-------------+

Solution

This is a known issue and is scheduled to be fixed in the ISE 11.2 software release. 

Please be sure to use the detail of the report when analyzing the timing reports.