mne-python: BUG: Mayavi hangs forever

Impossible to make mayavi/pysurfer work on an ubuntu 16.10

I followed the recommended installation steps:

• conda install mayavi
• pip install PySurfer
• export ETS_TOOLKIT=qt4 and export QT_API=pyqt

But mayavi’s scene hangs forever with this:

import mne
from mne.datasets import sample
data_path = sample.data_path()
fname = data_path + '/MEG/sample/sample_audvis-meg'
subjects_dir = mne.datasets.sample.data_path() + '/subjects'
stc = mne.read_source_estimate(fname)
stc.plot(subject='fsaverage', subjects_dir=subjects_dir)

Here is the system info:

mne.sys_info()
Platform:      Linux-4.8.0-49-generic-x86_64-with-debian-stretch-sid
Python:        2.7.13 |Continuum Analytics, Inc.| (default, Dec 20 2016, 23:09:15)  [GCC 4.4.7 20120313 (Red Hat 4.4.7-1)]
Executable:    /home/jrking/anaconda2/bin/python

mne:           0.15.dev0
numpy:         1.11.3 {lapack=mkl_intel_lp64, blas=mkl_intel_lp64}
scipy:         0.18.1
matplotlib:    1.5.1

sklearn:       0.19.dev0
nibabel:       2.1.0
mayavi:        4.5.0
pycuda:        Not found
skcuda:        Not found
pandas:        0.19.2

launching ipython with pylab=qt or qt4 makes PySurfer crash

/home/jrking/anaconda2/lib/python2.7/site-packages/pyface/qt/__init__.py in prepare_pyqt4()
     15     # Set PySide compatible APIs.
     16     import sip
---> 17     sip.setapi('QDate', 2)
     18     sip.setapi('QDateTime', 2)
     19     sip.setapi('QString', 2)

ValueError: API 'QDate' has already been set to version 1

Any idea where I should go from here?..

related issues and pages: https://github.com/mne-tools/mne-python/issues/3280, https://github.com/mne-tools/mne-python/issues/760, http://mne-tools.github.io/stable/install_mne_python.html, http://mne-tools.github.io/stable/advanced_setup.html