[FFmpeg-user] hwaccel vaapi and "No VA display found for device"

[desktop ready]

Hello,

I would like to confirm a bug/problem before submitting a bug report.
I am working on Debian Jessie/Stable amd64 on an Intel Skylake i3-6320
and would like to decode an HEVC 8-bit encoded UHD movie.

With a fresh ffmpeg github checkout I am able to use the following
command without errors:
ffmpeg -hwaccel vaapi -i castle.mp4 -f null -

However with ffmpeg release 3.2, I have the following errors:
[AVHWDeviceContext @ 0x7fdcf83adba0] No VA display found for device: .
[vaapi @ 0x30a61e0] Failed to create a VAAPI device
vaapi hwaccel requested for input stream #0:0, but cannot be
initialized.
[hevc @ 0x52bad20] Error parsing NAL unit #0.

However what is strange is that the ffmpeg version 3.2.2 on Debian
Jessie Backports also works without error (but with a high CPU
workload, which may indicate that hwaccel is not working as expected).

Ouput of ls -al /dev/dri:
ls -al /dev/dri
total 0
drwxr-xr-x   2 root root       100 nov.  23 00:40 .
drwxr-xr-x  19 root root      3520 nov.  23 03:59 ..
crw-rw----+  1 root video 226,   0 nov.  23 03:19 card0
crw-rw----   1 root video 226,  64 nov.  23 00:40 controlD64
crw-rw----+  1 root video 226, 128 nov.  23 00:40 renderD128

Is hwaccel vaapi working or not working on ffmpeg 3.2 to decode HEVC
8-bit encoded media ?

Thanks