>=media-libs/libva-2.17 uses DRI3 X11 extension in order to setup X server / application / libva / media driver communication. Unfortunately both media-libs/libva-intel-driver (https://github.com/intel/intel-vaapi-driver/issues/558) and media-libs/libva-intel-media-driver does not support such way of configuration via DRI3. Effectively, clients using vaPutSurface API are broken, i.e. mpv: [vo/vaapi] vaPutSurface() failed (invalid parameter) Reproducible: Always
Workaround is possible: setting LIBVA_DRI3_DISABLE=1 environment variable fixes the problem. However, I do not feel that stable package should require user to manually set any environment variables to be in the working state.