Are you sure this bug is not related to bug #85320? Also, are you certain i=
t is
fixed in 4.0.0-rc7+ (linux git). In the mentioned report users of RV620/630=
 and
RS780/880 (3450/2600 and 3200/4200 respectively) report GPU Resets and lock=
ups
when using vdpau hardware decoding.
Do you use also mesa git and might the fix be rather introduced by a mesa g=
it
pull? That would explain, why you could not bisect it in linux git.
I for my part have a Radeon HD 3200 Mobility (RS780M) and could still repro=
duce
it with linux git. Did you test the fix thoroughly? For example I could sta=
rt a
video with hardware accelerated video decoding in mpv 40 times without a GPU
Reset, but seeking in the video or disabling and reenabling the video track
could cause it, while normal playback usually did not trigger it.
Stable VLC however caused the GPU Reset on the first try using vaapi decodi=
ng
with vdpau wrapper. It would be at least a good sign, if VLC can=C2=B4t rep=
roduce
this anymore for you and maybe for the others at bug #85320 also.

So basically I=C2=B4m asking, whether the described methods still cause a G=
PU Reset
and what libraries you use in git version.