USB GM5 under linux

Miscellaneous
1

Hello,

I purchased 1 GM5 chip and pcb a long time ago, and have just soldered it (not easy).

pluggin into mac osx was instant sucess

After a stress test of about one hour with constant midi flow, i declared the board OK

Now pluging into a linux ubuntu (tangostudio) the device is recognised by alsa and 5 ports listed, all ok up to here.

either with aconnect or graphically with qjackctl i can wire something to the ploytec.

The problem is : The connection disappears itself after 5 seconds :pinch:

sometimes i can reconnect it, but it disappears again, and always, it is finally stucked, still listed but nothing gets in or out …

I tried different usb ports, external powered hub, no difference.

Does anyone has experience with this board and linux and could help ?

2

Hi there.

I’ve been using 2 GM5x5x5’s with several Linux distributions (mostly Debian and Arch) for a long time now and never had any problems.

Really just plug and play and worked 100%, running for days…

Sorry if thats not much help for you :confused:

3

Hi there.

I’ve been using 2 GM5x5x5’s with several Linux distributions (mostly Debian and Arch) for a long time now and never had any problems.

Really just plug and play and worked 100%, running for days…

Sorry if thats not much help for you :confused:

thank you for your answer, i’m still happy to know it’s really stable !

Yesterday, i found two capacitors with bad soldering (between ground and Vcc), so it was probably the source problem, as after that it worked ok for about one hour.

I’ll do some stress test before going live, but i’m now confident :slight_smile:

thanks again :slight_smile:

4

Cool! Lets hope its fixed now! :slight_smile:

5

hey, after replacing the capacitors with more adequate ones, the problem is still here. Somewhat different because it is now stable for about 1 minute, then it dissapears/reappers every 5 seconds or so…missing so notes when there is the gap.

Under osx, the box has been proved stable for one day long in live situation, so i’m now confident that the board is ok.

I’m going to test with another linux distro (now it is tangostudio), maybe there is something wrong on the usb driver side, or maybe the powering (as i’m using an mini itx board with a picopsu…rated at minimal power requirements)

6

Hmm thats strange. What kind of software are you using? Maybe test in a very simple command line environment with aplaymidi or something and see if it still occurs?

7

Hi!

I’m using it with Linux too, and didn’t notice any trouble.

When the interface disappear, what does ‘dmesg’ tells you? How does it works with MiosStudio?

Pilo

8

ok thank you guys for answering, so here we are :

The problem occurs with any software i’m using (SEQ or puredata mainly) with alsamidi or jack.

And it only happends when the ports is in use (midi data flowing out).

The dmesg was a great thing to check, thanks pilo :

usb 4-0:1.0: port 1 disabled by hub (EMI ?), re-enabling…

usb 4-1: usb disconnect address 13

usb 4-1: new full speed USB device using uhci_hcd and address 14

usb 4-1: configuration #1 chosen from 1 choice

So after looking for some help on the net, it looks like this is very related to EMI grounding problems.

I have to admit I haven’t done any grounding to the chassis in my build.

The case is all aluminium, should I connect the chassis to the USB ground ?

(The macbook laptop would not suffer from these grounding problems…)

EDIT ::

The problem occurs only when connecting midi out 1 on the GM5 board (the small midibox one)

when i use the midi outs 2 to 5 from the expansion board (on a veroboard), it is working ok !

I could have a bad soldering on the midi out connector of the GM5 board. I’m taking a look at that now. >> result = not better

here i’m looking forward to your advices

9

Ok so now it’s working fine with output 2 to 5?

I think you can try to put the case to ground, and see if it’s makes things works. Actually I never heard of this USB EMI issues, I just have a quick look on google and it seems a quite common problem!

I hope this can fix the problem :slight_smile:

10

yes it is working fine with outputs 2 to 5 :slight_smile:

Then for output 1 them problem is still here, even with grounding the case of the GM5. Now maybe I can ground the case of the computer itself. But this will be ground, not earth. BEcause as it is a 1U rack case powered with an external PSU. I only have 12V coming in the computer…

But this doens’t explain why outputs 2 to 5 are working…

I have another alternative : connecting output 1 on my veroboard like the other outputs, but i need to add more circuits on a full veroboard… probably ugly job… i’m not enthusiast :hmm:

As i’m not on a hurry about this, i’ll do more experiment, and let you know when i have more news, hopefully solved.

All those EMI discussion never go too far from what i’ve read, just trying other cables (what i’ve done already), ferrites, changing ports… may you find something usefull, let me know

11

Double check all the Soldering around output 1. I guess theres a connection problem somewhere, and the OSX driver is just a bit more ..lets say tolerant.

The grounding thing sounds a little far fetched. My GM5x5x5s don’t have cases at all :slight_smile: