Issue with sending audio to MOTU UltraLite MK4 on a Dell Latitude 5420 laptop

[krisfed]

We have a MATLAB user who is running into issues when trying to play audio with MOTU UltraLite MK4 on a Dell Latitude 5420 laptop (with either DirectSound or ASIO drivers). They are seeing the same issue with Audacity, so the issue seems to be related to PortAudio (as both MATLAB and Audacity use it)

Describe the bug
When trying to play audio with MOTU UltraLite MK4 on a Dell Latitude 5420 laptop (with either DirectSound or ASIO drivers) only a couple of frames are played before the device becomes unresponsive. They have to reboot the computer to be able to try again (terminating and re-initializing PortAudio or rebooting MOTU is not enough).

To Reproduce
With ASIO, they were trying to write out to 8 channels of analog output (with 128 buffer size).
With DirectSound, they tried to output to one of the stereo pairs with the same result. They also tried Audacity with DirectSound and it also stops working after a bit and a laptop reboot is required. Switching which audio pair is used also leads to a bad state.

Issue seems to be specific to the Dell Latitude 5420 laptop (with the USB 3.1 host controller ver 1.2).

We do not have the same laptop and MOTU interface, so we were not able to reproduce the issue ourselves and unfortunately we do not have more precise reproduction steps.

Expected behavior
Continue to be able to play more than a few samples of an audio.

Actual behavior
Was unable to play more than a few samples.

Desktop:

• OS: Windows 10 Pro
• PortAudio version: pa_stable_v190600_20161030, Oct 30, 2016
• If Windows or Linux, which Host API (e.g. WASAPI): ASIO and DirectSound

Additional context
Same workflows work fine on other laptops - they tried it on Dell Precision 5510, Dell Latitude 7210 (with a USB 3.1 host controller ver 1.1), and Dell Precision 3550 (with a USB 3.1 host controller ver 1.1). They are also able to use laptop speakers on Dell Latitude 5420 laptop with no issues. The firmware and drivers are all up to date and hardware diagnostics turned up no issues. Other audio software also seems to work fine on Dell Latitude 5420 with MOTU UltraLite MK4 - like Windows Media Player, Tracktion. The problem seems to be in the combination of PortAudio + Dell Latitude 5420 + MOTU UltraLite MK4.

Has anyone seen anything similar or know of any existing issues with this combination of hardware?

[philburk]

They have to reboot the computer to be able to try again (terminating and re-initializing PortAudio or rebooting MOTU is not enough).

PortAudio works at a very high level. If the device is hanging at such a low level then it is almost certainly a driver issue specific to that device. I don't think this is a PortAudio issue.

I recommend contacting the MOTU tech support.

[RossBencina]

One thing you could try is a build of PortAudio with only ASIO or only DSound enabled. That would rule out any potential issue with conflicts between the two subsystems. But overall I agree with Phil -- if the system requires a reboot to reset then it is a low level driver issue.

[RossBencina]

This could a known issue when initializing DirectSound and ASIO for the same device, which is almost certainly a driver-specific issue. If it is this issue then the workaround is to initialize DirectSound OR ASIO but not both. Currently this can be done by manipulating the initializers function table array prior to calling Pa_Initialize. There is an idea to make a public API for this. See ticket #10