I get the following error:

# cat /sys/kernel/debug/dri/0/pstate
cat: /sys/kernel/debug/dri/0/pstate: No such device

So "cpu-x -D" gives the following error:

grep: /sys/kernel/debug/dri/0/pstate: No such device
sed: read error on /sys/kernel/debug/dri/0/pstate: No such device
failed to retrieve all monitoring data for Card 1

There was no such issue with older kernels.

And on another machine, also with the 7.1.3 kernel, the error is
a bit different:

# cat /sys/kernel/debug/dri/0/pstate
cat: /sys/kernel/debug/dri/0/pstate: Operation not permitted

So "cpu-x -D" gives the following error:

grep: /sys/kernel/debug/dri/0/pstate: Operation not permitted
sed: can't read /sys/kernel/debug/dri/0/pstate: Operation not permitted
failed to retrieve all monitoring data for Card 0