10" DSI Riverdi Display interference

Technical Support
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1

new problem with this setup → iMX8m-mini + Dahlia + 10" DSI Riverdi display (standard flex cable)
We have a sporadic interference on the screen, and could not yet find when it happens - seems to be on Coldstart but not 100% sure. The problem can be seen on the video attached and has been replicated on 3 different setups (as described above)

tdx-info:
interference display.zip (619.4 KB)

Software summary
------------------------------------------------------------
Bootloader:               U-Boot
Kernel version:           5.15.129-6.5.0+git.6f8fd49366db #1-TorizonCore SMP PREEMPT Fri Dec 22 11:15:52 UTC 2023
Kernel command line:      root=LABEL=otaroot rootfstype=ext4 quiet logo.nologo vt.global_cursor_default=0 plymouth.ignore-serial-consoles splash fbcon=map:3 ostree=/ostree/boot.1/torizon/f66094621623afbf2f90fe298498edbedf8d8b115a61d3e2017c2d62b975a207/0
Distro name:              NAME="TorizonCore"
Distro version:           VERSION_ID=6.5.0-build.8
Distro variant:           VARIANT="Docker"
Hostname:                 verdin-imx8mm-14756390
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Hardware info
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HW model:                 Toradex Verdin iMX8M Mini WB on Verdin Development Board
Toradex version:          0060 V1.1C
Serial number:            14756390
Processor arch:           aarch64
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4

It seems to be an unreliable cable connection. Please try reinstalling the flex cable

5

thanks @alex.tx, but it is not the flex cable - as explained we have 3 different setup (all the same components) all with the same behavior, but it’s very sporadic situation. On my hardware I’ve tried 3 different flex cables (the one supplied with the display + 2 other from different brand - all with 15cm long) - also all have been tried without any bending, all strait from DSI adapter to display.
We also have a PCie modem installed on the Dahlia (EC25-G mini PCIe version), and thought it might be an interference from it when communicating at start-up, but we’ve tried several hard speed-test with no success on interference.

6

Can you still see the interference on the screen if the PCIe modem is completely removed from your system?

7

I will conduct more tests next Friday: without modem, and also testing with mallow

8

Dear @amartins I synced with @cyril.tx, who told me that you are in the process of using the nightly build for your tests. We will await your report about its results hope hope for success.

Best regards

Collin