[CentOS] C7, igb and DCB support for pause frame ?

Hi there,

I’m working on deploying our new cluster.
Masters have 5×1gbps (i210 and i350, thus using igb.ko), configured  
with mtu 9000, 802.3ad. Works fine *but* I can’t get DCB working  
(pause frame, aka flow control, which is supported by and enabled on  
our switches).

[root at master2 ~]# dcbtool gc eno1 dcb
Command:        Get Config
Feature:        DCB State
Port:           eno1
Status:         Device not capable

(I get the same with ELRepo 5.2.15 kmod).
Intel datasheet says flow control is available.
Can’t find much about it on the web or in kernel git repo. Could  
someone give me a hand ?

Regards,
Laurent.