Colibri-imx8 no serial output

Dear support, I am using a colibri-imx8 and the yocto BSP 5.7.0.
I am working to add a custom OS update solution with dual rootfs and the choice of the partition is made by u-boot. So I try to customize the u-boot recipe, I made some mistake and then the module will not boot anymore.
So I made the recover procedure, run easy installer from RAM erase the emmc from easy installer and then flash a Toradex multimedia image on the module.
Everything works as expected in the recovery procedure, the module boot and I am able to access to it over the ethernet interface via ssh.
The strange thing is that the module doesn’t print anything on the serial debug console, no u-boot output and also no linux kernel or shell output on that module.
Obviously I check the serial connection and using another SOM it is working as expected.

Any idea how to recover the serial print on that module?

Best regards,
Stefano.

Hi @SCordibella ,

Thanks for reaching out.

That is indeed very interesting behaviour. Some initial questions here:

  • Did the module output anything over serial before the “mistake” occurred?
  • Can you see any output on the serial if you install another image, like the Toradex Minimal image?
  • When you erased the eMMC did you get a special prompt appearing where you had to enter the module’s serial number?

Have a great day.

Best Regards
Kevin

Hi @kevin.tx,

Yes, the module prompt the u-boot output, the kernel log and the tty shell before.

No, I try to install the Toradex multimedia image from Easy Installer, but nothing is displayed.
I am sure that the image is running because I am able to access over ssh via the ethernet interface to the running image.

No the easy installer doesn’t ask me anything, as far as I can remember the erase procedure ends correctly.

Best Regards
Stefano.

Hi @SCordibella ,

Thanks for the information.

Just for the record. Are you using a carrier board from Toradex or are you using your own?

This other SOM you tested was also a Colibri iMX8X?

Best Regards
Kevin

Hi @kevin.tx

I try with two different Viola carrier board and also one Iris carrier board, both from Toradex of course.

Yes it is another colibri-imx8, same model as the one that doesn’t prompt over serial anymore.

Best regards,
Stefano

Hi @SCordibella ,

Thanks a lot.

Would it be possible that you send us two dmesg logs?

One of the module that still outputs over the serial and one from the module that does not ?

Best Regards
Kevin

Yes, sure. I will post on this topic tomorrow.

Best regards,
Stefano.[

Hi @kevin.tx here is the two dmesg file.

dmesg-no-prompt.log (30.2 KB)
dmesg.log (27.1 KB)

Best regards,
Stefano.

Hi @SCordibella ,
After analyzing both files, it seems that you ran the test in two different carrier boards,
In dmesg-no-prompt you have tthis line

 Machine model: Toradex Colibri iMX8QXP on Colibri Evaluation Board V3

and in dmesg you have this:

 Machine model: Toradex Colibri iMX8QXP on BCN3D board

Could you run the same test again, but using the same carrier board for both modules?

It would also be useful if you could write to us on support@toradex.com and provide us a link where we can download the image that you created , in order to reproduce your issue.

Best regards,
Josep

Hi @josep.tx,
the carrier board was the same, I just flash an image for another carrier board, but we just change some GPIO from the device tree, nothing that impact on the uart. Moreover the image provided by Toradex is not running on the Iris carrier board.
I run both SOM on the same Iris carrier board.

If you prefer I can flash the Toradex multimedia image on both SOM and then post the dmesg again.

Best regards,
Stefano.

Hello @SCordibella

If you prefer I can flash the Toradex multimedia image on both SOM and then post the dmesg again.

Please do that, and also send us a link where we can download your image, to reproduce your issue.

Best regards,
Josep

Hi @josep.tx
The issue happens also with your Toradex multimedia image.
Here is a log of the module that has the uart working in which I flash the Toradex Multimedia image.

dmesg.log (26.5 KB)

Best regards,
Stefano.

Hello @SCordibella ,
Thanks for the update.

Would it be possible for you to send us the recipe that caused your issue or a link to download the generated image?

I’m afraid that without one or the other we cannot make any progress in this topic.

Best regards,
Josep

Hi @josep.tx
I just send an email to support@toradex.com with the link to the image.

Best regards,
Stefano.

Received and downloaded.

Best regards,
Josep

Hello @SCordibella
I have flashed your image via Toradex Easy Installer in a Colibri iMX8QXP 2GB WB IT V1.0D, using an Aster V1.1B as a carrier board.
image
It doesn’t boot, but I still can see the output in the serial console:

U-Boot 2020.04-5.7.0+git.33bb8e968332 (Jan 01 1970 - 00:00:00 +0000)
CPU:   NXP i.MX8QXP RevC A35 at 1200 MHz at 69C
DRAM:  2 GiB
MMC:   FSL_SDHC: 0, FSL_SDHC: 1
Loading Environment from MMC... OK
In:    serial
Out:   serial
Err:   serial
Model: Toradex Colibri iMX8 QuadXPlus 2GB Wi-Fi / BT IT V1.0D, Serial# 06748677
 BuildInfo:
  - SCFW 216a2c2e, SECO-FW c9de51c0, IMX-MKIMAGE 6a315dbc, ATF 2fa8c63
  - U-Boot 2020.04-5.7.0+git.33bb8e968332
flash target is MMC:0
Net:   eth0: ethernet@5b040000 [PRIME]
Fastboot: Normal
Normal Boot
Hit any key to stop autoboot:  0
switch to partitions #0, OK
mmc0(part 0) is current device
Scanning mmc 0:1...
Found U-Boot script /boot.scr
3082 bytes read in 15 ms (200.2 KiB/s)
## Executing script at 83200000
Booting using distro boot script v1.1.5...
Boot type:
Switching active partition
Saving Environment to MMC... Writing to MMC(0)... OK
Using rootfs of partition B
83 bytes read in 14 ms (4.9 KiB/s)
libfdt fdt_check_header(): FDT_ERR_BADMAGIC
3232575 bytes read in 86 ms (35.8 MiB/s)
SCRIPT FAILED: continuing...
Colibri iMX8X #

After that I have entered the recovery mode and flashed a TorizonCore image:
image

And the serial port is still alive.

If you run ls -la /dev/tty ido you get any error?
Are you able to send data to the console via the SSH connection? (e.g. echo -ne 'blabla' > /dev/tty )

Best regards,
Josep

Hi @josep.tx
here is my tests:

root@colibri-imx8x-07252183:~# ls -al /dev/tty
crw-rw-rw- 1 root tty 5, 0 Nov  9 10:47 /dev/tty

it works without any errors and

root@colibri-imx8x-07252183:~# echo -ne 'blabla' > /dev/tty
blablaroot@colibri-imx8x-07252183:~# 

in this second case nothing is prompted on serial console.

Best regards,
Stefano.

Dear @josep.tx ,
do you have any update on this?

Best regards,
Stefano.

Hello @SCordibella ,
Unfortunately we cannot reproduce your issue. It seems that we have to proceed with the RMA

Best regards,
Josep