Waveforms 2015: "JtscInitScanChain failed" Error, "DptiIO failed" Error, Ubuntu 16.04.1, x86-64, Analog Discovery 2, Analog Discovery 2

[clf]

Waveforms 2015 on Ubuntu 16.04.1 intermittently fails when selecting an AD1/AD2 device in Waveforms's Device Manager screen, reporting either or both of the following error messages. Subsequent attempts intermittently fail or intermittently succeed.

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Device opening failed
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JtscInitScanChain failed ERC: 0x3E9
Device programming failed.
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Device opening failed
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DptiIO failed ERC: 0x7
Device configuration failed (PLL 3).
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System configuration:

digilent.adept.runtime_2.16.5-amd64.deb
digilent.waveforms_3.4.7_amd64.deb

Analog Discovery 1
Analog Discovery 2

$ uname -a
Linux 4.4.0-31-generic #50-Ubuntu SMP Wed Jul 13 00:07:12 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux

$ cat /proc/cpuinfo
processor    : 0
vendor_id    : GenuineIntel
cpu family    : 6
model        : 60
model name    : Intel(R) Core(TM) i7-4910MQ CPU @ 2.90GHz
stepping    : 3
microcode    : 0x1c
cpu MHz        : 2872.472
cache size    : 8192 KB
physical id    : 0
siblings    : 8
core id        : 0
cpu cores    : 4
apicid        : 0
initial apicid    : 0
fpu        : yes
fpu_exception    : yes
cpuid level    : 13
wp        : yes
flags        : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx pdpe1gb rdtscp lm constant_tsc arch_perfmon pebs bts rep_good nopl xtopology nonstop_tsc aperfmperf eagerfpu pni pclmulqdq dtes64 monitor ds_cpl vmx smx est tm2 ssse3 sdbg fma cx16 xtpr pdcm pcid sse4_1 sse4_2 x2apic movbe popcnt tsc_deadline_timer aes xsave avx f16c rdrand lahf_lm abm epb tpr_shadow vnmi flexpriority ept vpid fsgsbase tsc_adjust bmi1 avx2 smep bmi2 erms invpcid xsaveopt dtherm ida arat pln pts
bugs        :
bogomips    : 5786.61
clflush size    : 64
cache_alignment    : 64
address sizes    : 39 bits physical, 48 bits virtual
power management:

[attila]

Hello,

- Try to use different USB cable and computer plug.
- Use the USB plug on the back of the PC, not the one on the front panel.
- Use short cable, do not use long cable or cable extender.
- Use powered USB-hub, avoid un-powered hub.
- Use USB-Y cable to load power from two plugs.
- Use 5V auxiliary supply for AD2.

[clf]

Based upon @attila 's suggestions, it sounds like this may be known to be a power-related problem.

I may have identified the root cause:

-- Chris