drm-next-kmod-4.11 and vaapi hardware acceleration

[Oleg Lelchuk]

I run 12-CURRENT-r330303. My cpu is Haswell. After compiling
drm-next-kmod-4.11 and libva-intel-driver, I get garbled videos in both mpv
and vlc when the vaapi hardware acceleration is enabled. I had no such
problem with the previous version of drm-next-kmod. Is it possible that
libva-intel-driver-2.1 and drm-next-kmod-4.11 are not fully compatible with
one another? Please tell me what I should do to resolve this issue.