Uart driver Centos8 is mixing data vs Centos7

Issues related to hardware problems
Post Reply
gvorraro
Posts: 9
Joined: 2021/10/01 11:05:02

Uart driver Centos8 is mixing data vs Centos7

Post by gvorraro » 2021/10/26 11:58:00

Hi all,
I'm using an external (to to board that provides the HW UART service) device that when powerd on sends (repeatedly) the following string via uart

Lambeau Bootstrap UART!!

The communication works using Centos7 PC. I mean I see the expected strings printed on the screen.
When using the same device but with Centos8 PC I see the following strings

ae otpA!maBtr R!LbuosaUT

Basically the device is sending the string properly (Lambeau Bootstrap UART!!) but the system is providing a mixed one when using Centos8.

Both Centos 7/8 should be little endian since I got

lscpu | grep Endian
Byte Order: Little Endian

for both.

It seems to be related to the system memory that holds the incaming data (through PCIe), and/or BIOS setting.

analyzing the strings

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23
L a m b e a u B o o t s t r a p U A R T ! !

it seems the system takes one char out of three

1 4 7 10 13 16 19 22 2 5 8 11 14 17 20 23 0 3 6 9 12 15 18 21
a e o t p A ! m a B t r R ! L b u o s a U T

Any suggestion ?
Thanks in advance.

gvorraro
Posts: 9
Joined: 2021/10/01 11:05:02

Re: Uart driver Centos8 is mixing data vs Centos7

Post by gvorraro » 2021/10/28 15:21:24

Has anyone an idea ?
Thanks for caring.

User avatar
TrevorH
Site Admin
Posts: 33191
Joined: 2009/09/24 10:40:56
Location: Brighton, UK

Re: Uart driver Centos8 is mixing data vs Centos7

Post by TrevorH » 2021/10/28 15:31:30

No idea but what is the output from lsmod | grep -i serial so we can see which kernel module(s) are in use for it.
The future appears to be RHEL or Debian. I think I'm going Debian.
Info for USB installs on http://wiki.centos.org/HowTos/InstallFromUSBkey
CentOS 5 and 6 are deadest, do not use them.
Use the FAQ Luke

gvorraro
Posts: 9
Joined: 2021/10/01 11:05:02

Re: Uart driver Centos8 is mixing data vs Centos7

Post by gvorraro » 2021/10/28 15:42:45

Running "lsmod | grep -i serial" both systems printed nothing

gvorraro
Posts: 9
Joined: 2021/10/01 11:05:02

Re: Uart driver Centos8 is mixing data vs Centos7

Post by gvorraro » 2021/11/02 15:22:34

Any suggestions ?

User avatar
TrevorH
Site Admin
Posts: 33191
Joined: 2009/09/24 10:40:56
Location: Brighton, UK

Re: Uart driver Centos8 is mixing data vs Centos7

Post by TrevorH » 2021/11/02 15:35:33

Does it make any difference if you adjust the baud rate of the connection?
The future appears to be RHEL or Debian. I think I'm going Debian.
Info for USB installs on http://wiki.centos.org/HowTos/InstallFromUSBkey
CentOS 5 and 6 are deadest, do not use them.
Use the FAQ Luke

gvorraro
Posts: 9
Joined: 2021/10/01 11:05:02

Re: Uart driver Centos8 is mixing data vs Centos7

Post by gvorraro » 2021/11/16 10:33:23

Unfortunately no.
Can someone of you share the AlmaLinux 8.4 (Electric Cheetah) source code link to compile locally the kernel ?

gvorraro
Posts: 9
Joined: 2021/10/01 11:05:02

Re: Uart driver Centos8 is mixing data vs Centos7

Post by gvorraro » 2021/11/17 10:38:46

The issue I'm having now is that the Host input stream (from device to the Host (where I installed the uart driver)) works (when using MSI interrupt in place of legacy in the custom driver), but the Host output stream (from Host to device) doesn't.
I'm pretty sure Almalinux Centos8 has different uart port base settings than Centos7.5 (using it the input/output UART stream works), but I don't know which is the param that is blocking the output stream from kernel perspective.
Did someone have experienced with it ?

Post Reply