My design ran ok in ISE version 10.1, but now I am seeing unroutable connections involving some of my OSERDES I/O which drive through an IODELAY to an OBUFDS using IOSTANDARD DIFF_HSTL_II_DCI. Is this a known issue? .
Solution
An 11.1 regression for such a case has been seen on an internal design. A fix is scheduled for ISE version 11.2. If you encounter this problem prior to the release of version 11.2, please open a Webcase and refer to this Answer Record by number.