Hello AlexMamonov ,
Thank you for contacting the Intel Embedded Community.
The information that may help you is stated in the Intel® Open Source HD Graphics Programmers' Reference Manual (PRM) Volume 2, Part 3: Command Reference - Registers For the 2014 Intel Atom™ Processors, Celeron™ Processors, and Pentium™ Processors based on the "BayTrail" Platform (ValleyView graphics) document # IHD-OS-VLV-Vol2pt3-04.14.
It is important to let you know that the Intel Open Source Graphics Programmer's Reference Manual (PRM) For The 2014 Intel® Atom™ Processors, Celeron™ Processors, and Pentium™ Processors based on the Bay Trail Platform can be found at the 2014 Intel Processors based on the Bay Trail Platform website.
We hope that this information may help you.