Zybo "Poor placement for routing..." for MRCC/SRCC pin??

[malkauns]

I trying to use clock capable pin U15 on the Zynq using a Zybo board.  According to ug865-Zynq-7000-Pkg-Pinout.pdf U15 is one of the pins that are clock capable (MRCC/SRCC):

However I am getting the "Poor placement for routing..." error suggesting that I use "CLOCK_DEDICATED_ROUTE FALSE" which states is undesirable.  Any idea what is going on here?  I'm trying to use this with a high speed camera interface.  thx

[D@n]

I found this answer record helpful.  Basically, it suggests that you will need to place this clock pin into a buffer, such as a BUFG, and that there may be no buffers available.  You can set the CLOCK_DEDICATED_ROUTE to FALSE in order to examine what's going on in order to fix things, but then once you figure out (and fix) what's going wrong, you'll want to set it back to TRUE.

Dan