PT not behaving as expected when I launch and hold the 'n' key, to launch PB engine..

[Hugh-H]

Hello,

Unfortunately you found the same issue I did with the same result - a number of folks tell you N will allow you to select the playback engine but it does not under the following circumstances-
- HDX card installed
- no digilink audio interface attached

It will function as expected with a digilink interface attached.

It doesn’t matter when you press N, how long, and how enthusiastically, nor with what keyboard. Under my usual premise of “it’s probably my problem” I certainly hope someone can prove me incorrect.

http://duc.avid.com/showthread.php?t=403066

As far as I know a bug. It’s unfortunate because I want to do the same thing you mentioned- pull a system out of service, run tests and maintenance, without a digilink interface.

Hugh

[Rich Breen]

Originally Posted by Hugh-H

Hello,

Unfortunately you found the same issue I did with the same result - a number of folks tell you N will allow you to select the playback engine but it does not under the following circumstances-
- HDX card installed
- no digilink audio interface attached...

Certainly behaves as expected here.

[Darryl Ramm]

So I'll throw out a suggestion you folks might want to see if it works around this behavior. I've never tried it. But it won't hurt your systems (but be careful however to enter exactly what is below). This will just toss the DigiDal HD device driver out of the kernel and see if that lets Pro Tools get further. Hopefully this works as the software equivalent to removing the HDX card(s) to let you switch to built-in output..

With Pro Tools not running.

In a Terminal.app window type the following at your command prompt (shown as $ here, don't enter the $)...

$ kextstat -b com.digidesign.iokit.DigiDal

If the DigiDal kext (HD Driver) is loaded, and it should be, you will see an output line showing stats for it.

Then to unload it from the kernel, type the following....

$ sudo kextunload -b com.digidesign.iokit.DigiDal

You will have to enter your password (not root/admin password) when prompted.

Try opening Pro Tools while holding down N now.

You can always reboot the mac to get it back to how it was before or if you want to should be able to manually reload the driver by typing....

$ sudo kextload -b com.digidesign.iokit.DigiDal

[jeffro]

Don't have HDX here, so asked a colleague who said they also get the no interface dialog but cancelling that leads to the PBE and they can select different hardware. Are you releasing or holding N through the cancel?

[jeffro]

Pretty sure I have an HD Native TB around here, stay tuned...

[jeffro]

Okay, with Pro Tools Ultimate 2019.5 on my iMac w/macOS 10.13.6 with HD Native TB I get the Unable to find an audio interface... dialog. Clicking OK returns to that dialog, but clicking Cancel opens the Playback Engine window and allows me to select another option. Please check this again when you have a chance, thanks!

[Hugh-H]

Hello Jeffro,
Thanks for responding. Back when I first reported this issue I tried this on all 5 of our HDX2 and HDX3 systems with the same result - no matter the timing of N presses, if there’s a properly functioning HDX card with no audio interface, there’s no opportunity to select the playback engine. Plugging in an audio interface resulted in operation as expected. This was repeatable.
I won’t see any of those systems for a couple of weeks but can repeat the tests yet again, with low expectations based on spending much time on this previously.
OS10.12.6
PTHD18.3

Hugh

[jeffro]

Look forward to hearing your results. I can test again with HDN or enlist others for HDX.

[Hugh-H]

Hello Jeffro et.al.,

We received several systems back yesterday and tested them for proper operation of the "N" key modifier to allow playback engine selection during boot without Digilink I/O attached. We engaged in this testing for a few reasons - Jeffro is attempting to help us (always a good thing), a few members of the forum have reported it works for them, and we need the ability to perform system maintenance without connecting Digilink I/O as these systems are swapped among facilities frequently.

Here are the conditions and results -

All systems - HDX2, 2x HDMadi, SyncHD
All systems - OS10.12.6
All systems - PT18.3
All systems - Digilink driver associated with PT18.3
Some systems - 2012 MacPro 8-core cheese grater
Some systems - various 2013-2015 Macs with Sonnet TB2 expansion


First test sequence - each system was tested with Digilink I/O attached to determine control timing.
N key timing -
- N key press first instance was before launching PT.
- each following test the N key press was advanced 0.3 seconds later in the launch process.
- This was continued until the N key no longer launched the Playback Engine dialog.

First test results with Digilink I/O attached -
- there appear to be four launch steps visible to the user - PT launch initialization, "hardware initialization" visible only on some systems, plugin initialization, and session initialization (I recognize there are more, this is what's visible to the casual human observer).

- The N key press can be done anytime from before launch up to the plugin initialization finishing, after which an N key press does not allow pb engine selection. This was confirmed with two of the systems that have Waves installed but the usb auth was not attached - I could delay the N press until immediately after the last Waves auth popup and still bring up the PB engine dialog.


Second test sequence - each system was tested without Digilink I/O attached using the same N key timing process. I could list the test results for each test but here's the repeatable conclusion we finally reached after observation -

- HDX2 in a cheese grater MacPro brings up the "Unable to find an audio interface...." error immediately on the "hardware initialization" step, before plugin initialization. There is no "cancel" option, only "more information" and "OK". Either way the next step is the standard "ProTools has unexpectedly quit" error and PT crashes. There is never a method for the PB engine dialog.

- HDX2 in a TB2 chassis does NOT bring up the "Unable to find an audio interface...." error, plugins initialize correctly, then the Playback Engine dialog comes up allowing selection of something else.
- If you select another audio driver PT does the standard quit and relaunch and all functions correctly.
- If you select the HDX engine without the Digilink I/O PT brings up the "Unable to find an audio interface....", hitting Cancel then reverts to the PB engine dialog.


This TB/non-TB behavior was further partially confirmed by attempting to unload the HDX kext before launching PT.
- On a TB system this results in a console error because there are two kext classes of the DigiDal kext bundle, but enough unloads to make the HDX cards unavailable and they do not show up in the PB engine dialog.
- However on the 2012 MP attempting an HDX kext unload results in an immediate kernel crash.
- Obviously the kext unload works on the system that allows PB engine selection without Digilink I/O, so that doesn't achieve much for us.


I hope these results explain what's going on. I recognize non-TB PCIe is becoming less common in the Mac world but it's very common in the Windows world and for the tiny number of folks purchasing the new MP it will become common again. Would be interesting to hear how this functions on Windows without a TB chassis using built-in PCIe slots.
It's an unfortunate thing for us because we effectively cannot do PT maintenance on some of our machines without attaching Digilink I/O, sometimes we just want to plug in some headphones and check something.

Sincerely,
Hugh

[MixerGuy]

awesome - thanks for doing this!!!