[LinuxCNC/linuxcnc Issue#575] Python Interface – stat.axis dict reports 0 velocity in auto

As the title says – when running in auto mode or mdi mode, stat.axis has a velocity value of 0 for all axes. When jogging in manual mode, velocity value is correct.

Here are the steps I follow to reproduce the issue:

1. Have a loop which prints out stat.axis data for each axis. For example:
self.status.poll()
for i in range(3): print("Axis {}: {}".format(i, self.status.axis[i]))
2. Open a file and run it, or enter a command in MDI and run it.

This is what I expected to happen:

Loop prints the axis dictionary for each axis, velocity entry should match the real-world velocity of that axis.

This is what happened instead:

Velocity entry for all axes is 0 even when moving.

It worked properly before this:

LinuxCNC 2.7.11 worked.

Information about my hardware and software:

Tested on two machines. 1) prototype mill, 2) desktop with simulator only.
* I am using this Linux distribution and version: 1) Debian 9.6 (LinuxCNC image) with KDE desktop. 2) Kubuntu 16.04.6 LTS.
* I am using this kernel version: 1) 4.9.0-8-rt-amd64 #1 SMP PREEMPT RT 2) 4.9.47-rt37 #1 SMP PREEMPT RT
* I am running 1) v2.8.0-pre1-4106-g4440d31ff binary from buildbot.linuxcnc.org. 2) A binary I built myself from github v2.8.0-pre1-4628-g39ab67a.
* I am using a custom interface.
* I am using this interface hardware vendor and chipset (e.g., parallel port, ethernet port, FPGA card): 1) Mesa 7i92e + 7i76. 2) None, used as simulator only.