undefined symbol: drm_intel_gem_bo_unmap_wc

Hello.

I'm trying to use hardware HEVC encoder of i5-7300HQ through FFMpeg 3.3.3 on GNU/Linux 4.12.4. Have MediaServerStudioEssentials2017R3 installed.

quicksync-video-ffmpeg-install-valid.pdf tells, that I need to load iHD libva driver. However, it seems to be incompatible with current i915 (or what?):

user@host ~ % LIBVA_DRIVERS_PATH=/opt/intel/mediasdk/lib64 LIBVA_DRIVER_NAME=iHD vainfo
libva info: VA-API version 0.40.0
libva info: va_getDriverName() returns 0
libva info: User requested driver 'iHD'
libva info: Trying to open /opt/intel/mediasdk/lib64/iHD_drv_video.so
libva error: dlopen of /opt/intel/mediasdk/lib64/iHD_drv_video.so failed: /opt/intel/mediasdk/lib64/iHD_drv_video.so: undefined symbol: drm_intel_gem_bo_unmap_wc
libva info: va_openDriver() returns -1
vaInitialize failed with error code -1 (unknown libva error),exit

It's intersting, that open-source i965 libva driver does show something I interpret as support for HEVC encoding:

      VAProfileHEVCMain               :	VAEntrypointVLD
      VAProfileHEVCMain               :	VAEntrypointEncSlice
      VAProfileHEVCMain10             :	VAEntrypointVLD
      VAProfileHEVCMain10             :	VAEntrypointEncSlice

So, my question is: why I'm not able to use hardware HEVC encoding? Non-4.4 kernel? Kaby Lake CPU? Or something else is wrong in the system (or SDK)?