Comment # 8 on bug 1011158 from Max Staudt

On Intel platforms, VDPAU is implemented using a third-party wrapper,
libvdpau-va-gl, as the Intel driver only provide the VA interface. Pure output
without hardware decoding is pretty much bound to work, as the wrapper
implements video output via OpenGL.

It's when it comes to hardware decoding that problems sometimes arise, but in
your case, we don't even get there: The issues are in the VA layer. libva can't
even recognize your GPU by itself.

Can you please check whether the i915 driver in the kernel is working properly
with your system? Maybe post a dump of dmesg? On my Ivy Bridge test system, mpv
can play videos with "-vo=vaapi -hwdec=vaapi" just fine on Tumbleweed. This is
independent of whether xf86-video-intel is installed or not.