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reboot looses /dev/ttyACM0

HK6
New Contributor II
2,023 Views

I have been seeing an issue, which I am not sure is only in my environment

If others have see it please comment. Details below:

What:

any device on /dev/ttyACM0, with a USB OTG cable plugged in (i.e. Edison is acting as USB master),

a reboot ( regardless of any activity going on in the USB port) appears to make Edison shut down the /dev/ttyACM0.

A second reboot wakes up this /dev/ttyACM0. This is very consistent, i.e. the second reboot wakes up /dev/ttyACM0.

Again a third reboot shuts down ACM0 and a fourth re-awakens ... and so on.

How to reproduce:

Hardware:

My Edison is using a minibreak out board, with power being supplied by external power via J21.

I have an USB A female to Micro A male 10-00649 839-1105-ND (as per Edison docs.), with micro A plugged into Edison.

I have a USB slave device plugged (can be a phone with serial terminal activated on USB port) into USB A female.

Software:

Debian ubilinux installed per information available on this forum, on other threads.

Once the Edison is booted, I attempt to read and write the slave device. The failures are

noted on the odd numbered reboots.

0 Kudos
9 Replies
KEckh
Valued Contributor III
306 Views

This appears to be the same issue with standard yocto setup as well. There are a few threads on it:

I confirmed this happens still with new beta kernel that was posted on Friday

Note: I tried it with a USB2AX device, which is an Atmel 32u2 based board.

HK6
New Contributor II
306 Views

Thank you KurtE.

I went through the link you list above and I understand that there is an issue with power,

that Edison needs to have 7V to 12V on J21. I have 5.2V through a 20A capable power supply hooked to J21.

When I look into the document for the mini-break out board schematic (MINI_EDISON_BREAKOUT_HVM_8_26,pdf),

the device for power management used on the mini-breakout board is TPS62133.

The data sheet for TPS62133 shows input range from 3V to 17V.

Further examination of the data sheet appears to indicate a 5V input is OK for a 5V

regulated output (see application notes in TPS62133 data sheet).

So I think there is still a bug in the OS/software that needs to be fixed.

Is there a way in linux to test if /dev/ttyACM0 (ls /dev/ttyACM0, or lsusb or ???) is not turned on and force a turn ON?

Pedro_M_Intel
Employee
306 Views

Hello hk101,

We have been able to replicate this issue. Thank you for your feedback, the appropriate team has been informed, we are currently working on it, and it should be fixed in a future software release.

Peter.

SLi47
Novice
306 Views

Hi @Intel_Peter

Thanks for helping to fix this bug. We are also experiencing the same problem in our setup. Do you know when will the next Edison Linux kernel be released?

Thanks,

Shen

Pedro_M_Intel
Employee
306 Views

Hello shenli,

We are constantly working on improving our products, however there's no ETA on when the next Edison Linux kernel will be launched.

Peter.

MPapi
New Contributor I
306 Views

Is a kernel patch possible as this has been a thorn in my side for some time?

VenkataNar_K_Intel
306 Views

Hi Peter,

Is this issue fixed? i would like to know if there is any workaround or a fix

Thanks,

Manoj

Pedro_M_Intel
Employee
306 Views

Hello ManojKalluri,

No, unfortunately it is not resolved yet, we will have to wait until a future software release that hopefully fixes it; however there's no ETA on it.

Peter.

MAlde4
Novice
306 Views

Hi Peter,

This is a show stopper for us - any update on the software fix for this?

Is there anything we can do as a workaround? (Other than boot twice every time)

Thanks

Matt

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