PC Engines apu2 experiences

kevindd992002

@daddygo said in PC Engines apu2 experiences:

@kevindd992002 said in PC Engines apu2 experiences:

4.14.0.2 but this is not the first time I've tried this

You say, this is the case on several boxes (MOBO)
(so no HW issue I think, some PCB schematics or BIOS)

Worth a question for him:
https://github.com/miczyg1

BTW:
I can't check it either, because we only use apu24d4

Just created an issue:

https://github.com/pcengines/pcengines.github.io/issues/107

VAMike

@kevindd992002 using the serial port is pretty normal, and what you're describing is not at all common. I'd probably first make sure of the power supply (marginal power supplies cause all sorts of issues), then look at whether the serial cable is dodgy/shorted/etc.

DaddyGo

@vamike said in PC Engines apu2 experiences:

what you're describing is not at all common

Hi,
we are not talking about just one unit, so this is not relevant advice now...
(marginal power supplies cause all sorts of issues), then look at whether the serial cable is dodgy/shorted/etc.)

by the way he is quite an experienced pcEngines user @kevindd992002

kevindd992002

@vamike said in PC Engines apu2 experiences:

@kevindd992002 using the serial port is pretty normal, and what you're describing is not at all common. I'd probably first make sure of the power supply (marginal power supplies cause all sorts of issues), then look at whether the serial cable is dodgy/shorted/etc.

I know it's happening for two units and I'm using a power supply that I sourced from pcengines themselves. The only variable that I haven't eliminated is the serial cable that I'm using. I guess I can buy one of the good ones and try.

VAMike

@daddygo really? so you think "apu2 hardware generally doesn't work with serial and usb at the same time and up until now nobody ever noticed" is a likely thing?

stephenw10

Mmm, I would at least try a different cable.

Does it disconnect all usb devices when you connect the serial cable?

You may be creating a ground loop there since it's the UPS that is connected. Is the terminal device you're using also running from the UPS?

Steve

kevindd992002

@stephenw10 said in PC Engines apu2 experiences:

Mmm, I would at least try a different cable.

Does it disconnect all usb devices when you connect the serial cable?

You may be creating a ground loop there since it's the UPS that is connected. Is the terminal device you're using also running from the UPS?

Steve

I only have one usb device plugged in, the UPS. I'm trying now to see if using the other USB port will fix the issue because I only ever see the ugen0.2 disconnect message in the terminal. If ugen0.1 is the other port, then I don't see it getting affected.

Is there a command that I can invoke in the pfsense shell to see which usb port is a device connected to?

Yes, the terminal I'm using is connected to the same UPS.

DaddyGo

@vamike said in PC Engines apu2 experiences:

so you think "apu2 hardware generally doesn't work with serial and usb

hmmmm, ... no one assumed such a thing
just trying to figure out what is happening
while also having to "fumble" with ironic remarks

stephenw10

You can run usbconfig list to see info about the USB devices attached but it won't show the specific port only the bus.

But try just connecting anything, mouse, keyboard, data drive etc. Anything just to see if it also gets disconnected then the serial is attached.

Does it happen when you connect the serial cable if it isn't connected to the terminal client? That would almost certainly be the cable if so.

Steve

VAMike

@daddygo if you're trying to figure out what is happening the best thing to do is refrain from distracting commentary about what you think is "irrelevant"

@kevindd992002 if you got the two units at the same time I still wouldn't rule out wonky power supply as an issue. wall warts are notoriously unreliable, and I've seen >60% failure rates in the field (not DOA) from some batches in the past. those issues are complete PITA to debug because everything will work fine until the load reaches a certain point, then the PS can't keep up and weird things happen. much easier when they fail to the point that they melt, so the problem is obvious. trying different combinations of usb & serial is probably an easier place to start--throwing a thumb drive on with a serial console should work fine and is extremely well tested as a way to perform installs. if that doesn't work, definitely try a different serial cable and even a completely different serial source on the other end (e.g., try a different usb2serial converter on the machine you're using as a terminal). if it does work then you've narrowed down the source of the problem and it's neither serial nor usb generally, but that one specific usb device.

DaddyGo

@vamike said in PC Engines apu2 experiences:

the best thing to do is refrain from distracting commentary about what you think is "irrelevant"

hey buddy, leave it to those who know what they're doing, for example @stephenw10

stephenw10

Ok calm down! We are all trying to solve this problem.

Do not dismiss @VAMike. Review his old posts. You will see he knows what's what.

Steve

DaddyGo

@stephenw10 said in PC Engines apu2 experiences:

Ok calm down!

Okay, I understand, but I don't like it when someone arrives and immediately attacks...

@VAMike sorry bro, let's respect each other

+++edit: @stephenw10 by the way the best idea was the UPS ground loop

kevindd992002

@stephenw10 said in PC Engines apu2 experiences:

You can run usbconfig list to see info about the USB devices attached but it won't show the specific port only the bus.

But try just connecting anything, mouse, keyboard, data drive etc. Anything just to see if it also gets disconnected then the serial is attached.

Does it happen when you connect the serial cable if it isn't connected to the terminal client? That would almost certainly be the cable if so.

Steve

Ok, I did more tests and the results are more conclusive.

Both ports are labelled ugen0.2 when invoking usbconfig list which proves the point that that command lists only the bus.
Both ports are affected by the issue.
The issue only happens with the UPS USB device. I tried plugging in different devices (flash drives, keyboard, mouse, etc.) and all of them did not disconnect while the serial connection is opened.
When I connect the terminal, it disconnects the APC UPS and running the same command gives me this:

[2.5.2-RELEASE][root@pfSense.condo.arpa]/root: ugen0.2: <Unknown > at usbus0 (disconnected)
usbconfig list
ugen0.2: <Unknown > at usbus0 (disconnected)
ugen0.1: <0x1022 XHCI root HUB> at usbus0, cfg=0 md=HOST spd=SUPER (5.0Gbps) pwr=SAVE (0mA)
ugen1.1: <AMD EHCI root HUB> at usbus1, cfg=0 md=HOST spd=HIGH (480Mbps) pwr=SAVE (0mA)
ugen1.2: <vendor 0x0438 product 0x7900> at usbus1, cfg=0 md=HOST spd=HIGH (480Mbps) pwr=SAVE (100mA)

Look how it says "unknown" in ugen0.2. When this happens, unplugging and replugging the APC USB cable doesn't do anything.

It only happens when I connect the serial cable to the terminal client. If one end of the cable is connected to the APU2C4 but disconnected from the terminal client, no issue.

At this point, I would think the ground loop theory is making more sense to be the cause of the issue. What do you think? Can it still be the cable?

DaddyGo

@kevindd992002 said in PC Engines apu2 experiences:

What do you think? Can it still be the cable?

do you have a multimeter at your hand, with a diode tester (discontinuity measurement)?

+++edit:
the metal enclosures of UPS and APU stuff,- bringing them up to equipotential is not a bad idea

kevindd992002

@daddygo said in PC Engines apu2 experiences:

@kevindd992002 said in PC Engines apu2 experiences:

What do you think? Can it still be the cable?

do you have a multimeter at your hand, with a diode tester (discontinuity measurement)?

+++edit:
the metal enclosures of UPS and APU stuff,- bringing them up to equipotential is not a bad idea

I do. So you want me to see if there's low resistance between the APU's metal enclosure and UPS' ground point, correct? The UPS doesn't have a metal case because it's all plastic. It's an APC BR1500GI. So the ground points would be the screws and the third prong in the outlets themselves.

Do I test before and after the serial cable connection?

DaddyGo

@kevindd992002 said in PC Engines apu2 experiences:

The UPS doesn't have a metal case because it's all plastic.

I can already see the type (double insulated), the earthing is on the IEC13 connector(s) - the secondary circuit (after the inverter) is completely internally disconnected from primer

the middle leg of IEC13 is the ground, measure a resistance between this point and the APU metal housing

but you can also "ringing" the cable in question to see if there is a break somewhere

+++edit:
that reminds me, you say you have two of these boxes, how about testing the second one completely independently of the UPS on, say, on the kitchen table?

this would bring us closer to a solution

VAMike

@daddygo said in PC Engines apu2 experiences:

Okay, I understand, but I don't like it when someone arrives and immediately attacks...

you'll note that my first interaction with kevindd992002 in this thread dates from before you joined the forum...

VAMike

@kevindd992002 another possible low-cost thing to try would be to plug the ups cord and the apc into a powered usb hub, if you have one handy; that might isolate the connection a bit. those usb monitoring connections have historically played fast and loose with specs.

kevindd992002

@vamike said in PC Engines apu2 experiences:

@kevindd992002 another possible low-cost thing to try would be to plug the ups cord and the apc into a powered usb hub, if you have one handy; that might isolate the connection a bit. those usb monitoring connections have historically played fast and loose with specs.

What do you mean by ups cord and the apc? Are you referring to the same usb cable from the apc?

I actually thought of this too, adding a powered usb in between as I know the USB ports of the apu2c4 are problematic at best. I don't have one on hand but I can easily source for one, no problem.