How to test DSI connection on custom-board?

[Arnas Celkys]

I am using MB1407C (stm32mp157x-DK2 extension board with touch-screen) connected to my custom board. When board is booting I am getting the "ST life.augmented" screen on the U-boot and black screen when kernels starts. Also I am getting the telnet commands when I am updating the flashlayout using the CubeMxFlashLoader - so my guess is the DSI connection is working, but why do i get the black screen instead of the Wayland Weston desktop- that is shown when stm32mp157x-DK2 loads up the OS? What am i missing? What is other way to test the DSI connections?

[Arnas Celkys]

************* update ************************

Attaching stdout

        Starting Weston Wayland Compositor (on tty7)...

[ OK ] Started Sound Service.

[ OK ] Reached target Multi-User System.

        Starting Update UTMP about System Runlevel Changes...

[ OK ] Started Update UTMP about System Runlevel Changes.

[FAILED] Failed to start Weston Wayland Compositor (on tty7).

It would appear it fails Weston Wayland Compositor

then I tied:

>>systemctl status weston@root.service

<<

[[0;1;31m*[[0m weston@root.service - Weston Wayland Compositor (on tty7)

    Loaded: loaded (/lib/systemd/system/weston@.service; static; vendor preset: disabled)

[[0;1;31m*[[0m weston@root.service - Weston Wayland Compositor (on tty7)

    Loaded: loaded (/lib/systemd/system/weston@.service; static; vendor preset: disabled)

[[0;1;31m*[[0m weston@root.service - Weston Wayland Compositor (on tty7)

[[0;1;31m*[[0m weston@root.service - Weston Wayland Compositor (on tty7)

    Loaded: loaded (/lib/systemd/system/weston@.service; static; vendor preset: disabled)

    Active: [[0;1;31mfailed[[0m (Result: exit-code) since Sun 2020-09-20 10:44:12 UTC; 6min ago

   Process: 601 ExecStartPre=/sbin/check-gpu [[0;1;31m(code=exited, status=1/FAILURE)[[0m

Sep 20 10:44:11 stm32mp1 systemd[1]: Starting Weston Wayland Compositor (on tty7)...

Sep 20 10:44:12 stm32mp1 systemd[1]: [[0;1;39m[[0;1;31m[[0;1;39mweston@root.service: Control process exited, code=exited, status=1/FAILURE[[0m

Sep 20 10:44:12 stm32mp1 systemd[1]: [[0;1;38;5;185m[[0;1;39m[[0;1;38;5;185mweston@root.service: Failed with result 'exit-code'.[[0m

Sep 20 10:44:12 stm32mp1 systemd[1]: [[0;1;31m[[0;1;39m[[0;1;31mFailed to start Weston Wayland Compositor (on tty7).[[0m

I seems to indicate to problem of vendor, but this same SD runs on eval-board ok... The custom-board has the same pinout and socket for DSI (double-checked).

Also I have checked the 3V3 for the DSI screen and seems to be stable 3V3.

Not sure should I proceed to tripple check the HW (pcb traces etc.) or issue is on SW...

[Arnas Celkys]

TOP - eval-board schematicsBOT - my custom board shematics

[Tesla DeLorean]

>>or issue is on SW...

That you successfully get any image displayed suggests its not a HW connectivity problem.

Start screen suggest that has all the clocking and timing in order for that part (u-Boot ?)

[Arnas Celkys]

Yep it works in U-Boot and goes dark as soon as it starts up kernel, my hunch tells that it is SW too. I will try a few more things and post update :)

[Kevin HUBER]

Hello @Arnas Celkys​ ,

Do you still need help on this issue?

Regards,

Kévin

[Arnas Celkys]

Good morning, @Kevin HUBER​ 

I just removed HDMI node (because I am not using it at all) as alternative on Kernel device tree - it worked out for me. Thanks!

Regards,

Arnas

[Kevin HUBER · Accepted solution]

Good morning @Arnas Celkys​ ,

Nice.

I think the probe of the HDMI probably caused an error that was preventing LTDC/DSI to be configured correctly at linux level.

Great that you find the problem.

Regards,

Kevin