Comment # 19 on bug 90537 from Christian König

(In reply to pstglia from comment #16)
> > The mesa version is uninteresting, but what kernel version are you using?
> > 
> > Older kernels have stability problems when you unmap the BO VA. That's why
> > we don't use it in mesa by default.
> > 
> > Regards,
> > Christian.
> 
> We are using kernel 4.0.3

Strange, that kernel should work perfectly fine.