Hello, it's me again,
I'm not sure if this is the right forum to post this, but I think this bug might be caused by the usb 3 implementation in linux. I use Ubuntu 16.04, and I communicate with my LabJack T7 in Python.
At first I noticed that I sometimes have the LJME_RECONNECT_FAILED error when attempting to open a labjack with ljm.openS('ANY', 'ANY', 'ANY'). If I try again and again, it ends up working, then I can use my labjack. Strange thing is, if I disable the usb 3 (xhci) in my bios settings, I completely get rid of this error.
Find attached the .py file I used to do my testings, and the summary of my tests : they simply show that I no longer have errors when usb 3 is disabled.
Can you confirm this error only occurs with Linux, I only tried ubuntu's (16.04 and 14.04) with different kernel versions (4.4 and 3.16), do you have others ideas that I could investigate to find the culprit.
Thanks in advance
Francois
Hi Francois. Thanks for reporting this. We weren't able to reproduce the error yet. Here's a few things you could try:
Some questions:
I've done all of the above you suggested, that didn't solved the problem. I also tried plugging the labjack into an usb 2.0 powered hub, without result.
I get the LJME_RECONNECT_FAILED nearly half of the time, so I'm surprised you couldn't reproduce the error.
Find attached a sample of dmesg command when I execute my python script (first message) : every time a LJME_RECONNECT_FAILED occurs, it seems that the labjack device is disconnected, then re-connected again
We're looking into this. We'll update this thread as we go.
I've fixed the LJME_RECONNECT_FAILED error. The fix will be available in the next version of LJM after 1.1404, and I will update this thread when that LJM version is released. However, the problem is not completely solved: instead of failing with LJME_RECONNECT_FAILED, there is a delay (~2.5 seconds with the default send/receive timeout) when the problem occurs.
To mitigate the problem detailed in francoisbiar's original post:
Thanks for your outstanding reactivity (for this, and the other posts I made). I'm looking forward to the next update.
The mitigation mentioned above is in LJM 1.1405, now available here:
https://labjack.com/support/software/installers/ljm
Hello,
I installed the beta version (2017-01-31), and it looks like what you've done completely fixed the problem. I never had any LJME_RECONNECT_FAILED so far with this version (tested with 3 PC's).
Thanks again