vainfo error (resource allocation failed)

I'm trying to enable hardware acceleration on my debian wayland machine with an integrated GPU Intel Graphics. I set the LIBVA_DRIVER_NAME variable to iHD, and I got this error : $ vainfo libva info: VA-API version 1.17.0 libva info: User environment variable requested driver 'iHD' libva info: Trying to open /usr/lib/x86_64-linux-gnu/dri/iHD_drv_video.so libva info: Found init function __vaDriverInit_1_17 libva error: /usr/lib/x86_64-linux-gnu/dri/iHD_drv_video.so init failed libva info: va_openDriver() returns 2 vaInitialize failed with error code 2 (resource allocation failed),exit I did some research, and when I unset the XDG_RUNTIME_DIR variable, the command works (even if it complains about it) : $ XDG_RUNTIME_DIR= vainfo error: XDG_RUNTIME_DIR is invalid or not set in the environment. libva info: VA-API version 1.17.0 libva info: User environment variable requested driver 'iHD' libva info: Trying to open /usr/lib/x86_64-linux-gnu/dri/iHD_drv_video.so libva info: Found init function __vaDriverInit_1_17 libva info: va_openDriver() returns 0 vainfo: VA-API version: 1.17 (libva 2.12.0) vainfo: Driver version: Intel iHD driver for Intel(R) Gen Graphics - 23.1.1 () vainfo: Supported profile and entrypoints VAProfileNone : VAEntrypointVideoProc VAProfileMPEG2Simple : VAEntrypointVLD VAProfileMPEG2Main : VAEntrypointVLD VAProfileH264Main : VAEntrypointVLD VAProfileH264Main : VAEntrypointEncSliceLP VAProfileH264High : VAEntrypointVLD VAProfileH264High : VAEntrypointEncSliceLP VAProfileJPEGBaseline : VAEntrypointVLD VAProfileJPEGBaseline : VAEntrypointEncPicture VAProfileH264ConstrainedBaseline: VAEntrypointVLD VAProfileH264ConstrainedBaseline: VAEntrypointEncSliceLP VAProfileVP8Version0_3 : VAEntrypointVLD VAProfileHEVCMain : VAEntrypointVLD VAProfileHEVCMain : VAEntrypointEncSliceLP VAProfileHEVCMain10 : VAEntrypointVLD VAProfileHEVCMain10 : VAEntrypointEncSliceLP VAProfileVP9Profile0 : VAEntrypointVLD VAProfileVP9Profile0 : VAEntrypointEncSliceLP VAProfileVP9Profile1 : VAEntrypointVLD VAProfileVP9Profile1 : VAEntrypointEncSliceLP VAProfileVP9Profile2 : VAEntrypointVLD VAProfileVP9Profile2 : VAEntrypointEncSliceLP VAProfileVP9Profile3 : VAEntrypointVLD VAProfileVP9Profile3 : VAEntrypointEncSliceLP VAProfileHEVCMain12 : VAEntrypointVLD VAProfileHEVCMain422_10 : VAEntrypointVLD VAProfileHEVCMain422_12 : VAEntrypointVLD VAProfileHEVCMain444 : VAEntrypointVLD VAProfileHEVCMain444 : VAEntrypointEncSliceLP VAProfileHEVCMain444_10 : VAEntrypointVLD VAProfileHEVCMain444_10 : VAEntrypointEncSliceLP VAProfileHEVCMain444_12 : VAEntrypointVLD VAProfileHEVCSccMain : VAEntrypointVLD VAProfileHEVCSccMain : VAEntrypointEncSliceLP VAProfileHEVCSccMain10 : VAEntrypointVLD VAProfileHEVCSccMain10 : VAEntrypointEncSliceLP VAProfileHEVCSccMain444 : VAEntrypointVLD VAProfileHEVCSccMain444 : VAEntrypointEncSliceLP VAProfileAV1Profile0 : VAEntrypointVLD VAProfileAV1Profile0 : VAEntrypointEncSliceLP VAProfileHEVCSccMain444_10 : VAEntrypointVLD VAProfileHEVCSccMain444_10 : VAEntrypointEncSliceLP Why does that happen ? I'm not sure I understand completely what XDG_RUNTIME_DIR does, and I suspect it is not really the root cause of the problem, but I can't find any other clues as to what I can try next. I'm happy to update my question if more system info is needed.