Mac Mini M2 Pro and Soundcraft UI24R issue

[bpence310]

Anyone know how to make a Mac Mini M2 Pro be able to go to sleep and wake back up without me having to reset my Soundcraft UI24R, unplug the USB-A dongle, swap ports, etc... Everytime my Mac goes to sleep my Soundcraft disconnects (likely due to the USB powerdown) and will not reconnect without having to do all kinds of things to get it to reconnect.

[Etienne1973]

Connecting your Soundcraft device via an active USB hub?

[bpence310]

Etienne1973,

No, I have it connected directly to one of the USB-C/Thunderbolt ports on the back of the Mac. I am using an active USB cable, but it is directly connected.

[PAK]

No, I have it connected directly to one of the USB-C/Thunderbolt ports on the back of the Mac. I am using an active USB cable, but it is directly connected.

Right, but the suggestion was to connect it to a powered USB hub, and then connect that to the Thunderbolt port. So the hub is between the two and the device has a source of power other than the computer, using a standard (not active) USB cable, which gets its power from the hub.

It’s worth a try, though it likely won’t make a difference. I’m assuming you also tried it directly via a USB-A port already, to see if it was any better?

The only other thing you might try is to unplug the device, from the USB port, before you sleep the computer, then try reconnecting either before or after it’s back on. Since it seems likely it’s about how its handling the whole shut down / resume thing, from Mac OS, the hope is avoiding part of that somehow makes things better. Otherwise, it's not really something you can likely fix this side of a driver or device firmware update.

[bpence310]

PAK, I have tried using the external powered USB-C Dock I have and it doesn't help. As I mentioned, the problem is that the Mac turns off (apparently non-gracefully) power to the USB ports when it sleeps, and it doesn't seem that the Soundcraft UI24r is designed to gracefully recover when the Mac un-sleeps. The issue is the Mac, not the cable or the Soundcraft. My question was how to get the Mac to NOT kill power to the USB ports. In this instance, I am willing to sacrifice the environment for the 20 minutes or so it takes me to get the Soundcraft to work again after the Mac awakens from a slumber. I am getting around it, for now, by just letting it kill the screen but not actually sleeping, ever.

[PAK]

My question was how to get the Mac to NOT kill power to the USB ports. In this instance, I am willing to sacrifice the environment for the 20 minutes or so it takes me to get the Soundcraft to work again after the Mac awakens from a slumber. I am getting around it, for now, by just letting it kill the screen but not actually sleeping, ever.

If you can wake the computer by moving a mouse, or touching a keyboard, then it’s obviously not technically “killing” power to the ports, otherwise it couldn’t do that. Instead it’s sending a suspend signal, to the device, when you set it to sleep. How a device reacts to that depends on the device.

In terms of what’s actually going on, with the power, Apple Silicon Macs aim to keep the standby (sleep) usage below ~2.1W max. Off hand I don’t know how much of that standby power it continues to drip feed to the ports, and how it allocates priority. But the USB-A port could well make a difference Vs the Thunderbolt port etc in this type of situation.

In terms of basic power delivery - if you use a “charge only” port on a powered hub, as the power source (not the computer signal source - so you'd need to rig some sort of dual cable solution), it should keep feeding power independent of what the computer tells it. But, if the computer is sending a signal to suspend, and the device respects it, then it’s still going to power down regardless! Thus the suggestion to remove the cable before powering down

In terms of an OS setting, there’s no “allow the computer to turn off this device to save power” exceptions I’m aware of (like on Windows) to stop it turning off the device when you suspend. Though, to some extent, Apple would likely argue they don’t need it since doing so would increase the power draw in sleep mode..

When fully booted, at idle, your Mac Mini is typically going to pull less than 10W from the wall, which is (at the very most) about an 8W difference Vs sleeping it. It’s likely some (especially desktop) PC’s will pull more power even when in they’re in sleep mode, so you don't need to feel too bad! As your screen uses the vast majority of the power at idle you’ve already figured the “compromise” solution. Though I would still ask the company, who makes the audio device, when they will provide a firmware update to improve how it handles sleep on current Macs - especially if they’re still selling it.

[BertKoor]

It's not got to do with power and USB, this device is a bit large to get it's power over USB alone. And I don't think it's supposed to work like this.

And I guess you already had experimented with powering off the blue box first, before putting the Mac to sleep? Then power on the blue box again after waking up the Mac.

If it's got the latest firmware already, then get in touch with Soundcraft support:
https://www.soundcraft.com/en/support

[PAK]

It's not got to do with power and USB, this device is a bit large to get it's power over USB alone. And I don't think it's supposed to work like this.

You weren't kidding on the size - that's a chonky device with zero chance of being USB powered! So it's definitely not about power delivery in this case. It's about how its handling (or rather isn't) the sleep / resume signals over USB.

[bpence310]

I agree with these statements.. It's not getting it's power over USB. It's designed as a live audio mixer with the added capability of being used as an audio interface, which is what I'm mainly using it for. My problem is that I have it rack mounted, and I have a 42U server rack and I put the Mac inside it on a shelf and use a HDMI to Ethernet extender to get the monitor over by my drum kit. Unplugging anything and replugging anything is a nightmare, and having to power down the soundcraft is a nightmare because the on/off switch is on the side of device inside of the rack rails. I have it wired to a separate rack power strip that has individual on/off switches for each port as a workaround, also, but it just shouldn't be this way. I think contacting Soundcraft might be the best way to get an update for handling the usb signaling.

[BertKoor]

The "USB I/F" connection on the front is what's going to the Mac, right? And well within reach?
How about unplugging that before putting the Mac to sleep? I agree that's not optimal, but if that works then it works.
But do contact Soundcraft tech support...