Tvheadend

Hi all, first post here! Thank you all for this awesome PVR server

This is more a Linux question than a Tvheadend question. I've a working set up on an Intel server, using a Z97 chipset motherboard. Found a small issue that, no matter which USB ports I use, the tuners always connect to "Bus 001", e.g.:

$ lsusb | sort
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 001 Device 003: ID 1415:0003 Nam Tai E&E Products Ltd. or OmniVision Technologies, Inc. 
Bus 001 Device 007: ID 1415:0003 Nam Tai E&E Products Ltd. or OmniVision Technologies, Inc. 
Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 002 Device 002: ID 0781:5580 SanDisk Corp. SDCZ80 Flash Drive
Bus 003 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 003 Device 002: ID 8087:8009 Intel Corp. 
Bus 004 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 004 Device 002: ID 8087:8001 Intel Corp.

As a best practise, the tuners should be on different buses. Not sure why I can't connect them to Bus 003 and 004?