Serial port prints garbled logs

Robotics & Edge Computing Jetson Systems Jetson Thor
,
1

1、Print a garbled log during kernel startup

[ 2.440719] io scheduler bfq registered
[ 2.454282] EINJ: ACPI disabled.
[ 2.465103] tegra264-pmc c800000.pmc: there is not valid maps for state default
[ 2.469436] Serial: 8250/16550 driver, 4 ports, IRQ sharing enabled
[ 2.471469] msm_serial: driv��[ ��er i�� 2.4��niti��7837��aliz��8] p��ed
��er i��[ ��k: l�� 2.4��egac��7172��y co��3] S��nsol��uper��e [t��H (H��tyUT��)SCI��C0] ��(F) ��enab��driv��led
[ ��niti�� 2.��aliz��4900��ed
��28] ��[ ��prin�� 2.4��tk: ��7336��lega��0] S��cy b��TM32��ootc�� USA��onso��RT d��le [��rive��tegr��r in��a_ut��itia��c0] ��lize��disa��d
[��bled�� ��
[ ��2.47�� 2��8378��.508��] pr��859]��intk�� arm��: le��-smm��gacy��u-v3�� con�� 810��sole��5000�� [tt��000.��yUTC��iomm��0] e��u: i��nabl��as 4��ed
��nsol��[ ��t, o�� 2.4��as 4��9002��8-bi��8] p��t (f��rint��eatu��k: l��res ��egac��0x00��y bo��0e1f��otco��af)
��-v3 8105000000.iommu: allocated 65536 entries for cmdqrm-��isab��smmu��led
[ 2.549332] arm-smmu-v3 8106000000.iommu: ias 48-bit, oas 48-bit (features 0x000e1faf)qs
[ 2.557233] arm-smmu-v3 8106000000.iommu: allocated 65536 entries for cmdq

2、Regularly print garbled logs after system login. Can these garbled logs be prohibited from printing?

mi@localhost:~$
mi@localhost:~$
mi@localhost:~$
mi@localhost:~$
mi@localhost:~$ ��GPC ph => logic map: 0=>0 1=>2 2=>1
��INFO: END TASK:MB��
INFO: enter idle task.
INFO: END TASK:MB��
��ph =��ter idle ta��GPC ��sk.
��> logic map: 0=>0 1=>2 2=>1
��
mi@localhost:~$
mi@localhost:~$
mi@localhost:~$
mi@localhost:~$ ��GPC ph => logic map: 0=>0 1=>2 2=>1
��INFO: END TASK:MB��
INFO: enter idle task.
INFO: END TASK:MB��
��ph =��ter idle ta��GPC ��sk.
��> logic map: 0=>0 1=>2 2=>1
GPC ph => logic map: 0=>0 1=>2 2=>1
��INFO: END TASK:MB��
INFO: enter idle task.
INFO: END TASK:MB��
��ph =��ter idle ta��GPC ��sk.
��> logic map: 0=>0 1=>2 2=>1
GPC ph => logic map: 0=>0 1=>2 2=>1
��INFO: END TASK:MB��
INFO: enter idle task.
INFO: END TASK:MB��
��ph =��ter idle ta��GPC ��sk.
��> logic map: 0=>0 1=>2 2=>1
GPC ph => logic map: 0=>0 1=>2 2=>1
��INFO: END TASK:MB��
INFO: enter idle task.
INFO: END TASK:MB��
��ph =��ter idle ta��GPC ��sk.
��> logic map: 0=>0 1=>2 2=>1
GPC ph => logic map: 0=>0 1=>2 2=>1
��INFO: END TASK:MB��
INFO: enter idle task.
INFO: END TASK:MB��
��ph =��ter idle ta��GPC ��sk.
��> logic map: 0=>0 1=>2 2=>1
GPC ph => logic map: 0=>0 1=>2 2=>1
��INFO: END TASK:MB��

Kernel thread periodic CPU load 100%
2

For Thor, it is normal to see such behavior in UART log.

To avoid this, you need to use the tcu muxer to split each log into different pts.

3

The serial port keeps printing the following log. Can this printing be disabled? How can I disable it?

��ph =��ter idle ta��GPC ��sk.
��> logic map: 0=>0 1=>2 2=>1
GPC ph => logic map: 0=>0 1=>2 2=>1
��INFO: END TASK:MB��
INFO: enter idle task.
INFO: END TASK:MB��

4

Have you changed to use tegra combined uart muxer?

5

The thor devkit also has this problem.
Hopefully, you can disable the serial port from printing these logs.

��ph =��ter idle ta��GPC ��sk.
��> logic map: 0=>0 1=>2 2=>1
GPC ph => logic map: 0=>0 1=>2 2=>1
��INFO: END TASK:MB��
INFO: enter idle task.
INFO: END TASK:MB��

8

Those messages are from BPMP FW.

For thor, please refer to Tegra Combined UART — Jetson Thor to use nv_tcu_demuxer tool and capture log from /dev/pts/15 CCPLEX: 0, and you won’t get those messages.

11

The actual use case is to use an MCU to receive Thor serial port logs. Currently, nv_tcu_demuxer is not available on the MCU.

Is there more detailed information on the BPMP FW?

How can I disable these printouts?

13

Can you provide the nv_tcu_demuxer source code?

14

Do the following serial port information need to be printed?

��ph =��ter idle ta��GPC ��sk.
��> logic map: 0=>0 1=>2 2=>1
GPC ph => logic map: 0=>0 1=>2 2=>1
��INFO: END TASK:MB��
INFO: enter idle task.
INFO: END TASK:MB��

15

nv_tcu_demuxer is just a tool under your Linux_for_Tegra BSP directory. Not sure why you need its source code…

16

The actual usage scenario is not just PC connected to Thor, using an MCU to receive the serial port information of Thor, hoping to transplant nv_tcu_demuxer to MCU

17

The source code of this tool won’t be provided.

We are still checking if we could disable below log.

��ph =��ter idle ta��GPC ��sk.
��> logic map: 0=>0 1=>2 2=>1
GPC ph => logic map: 0=>0 1=>2 2=>1
��INFO: END TASK:MB��
INFO: enter idle task.
INFO: END TASK:MB��

18

In JP7.1 version, the serial port log will not be printed frequently.

20

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