Thank you, Tolga, very much for this hint!
LSI.com is down now.
I've found lsiutil for many OSes at http://www.dzhang.com/blog/2013/03/22/where-to-get-download-lsiutil.
I works under Windows too.
It helped in my case to fix negotiated link speed 1.5 Gbps with Samsung 850 EVO SSD and LSI Logic SAS3444E HBA based on LSI 1068E controller.
No need for full reboot. It's sufficient to reset port via 99 command in lsiutil.