Verdin iMX8MM: kernel warning when rotating display panel in devicetree

Technical Support
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1

Hello,

in this thread I was able to connect the display SL101PM1794FOG-V15 (1920x1200) to the MIPI-DSI of a Verdin iMX8MM that runs with BSP6.0.

Since the panel is in portrait mode by default I rotated it in the device tree with

&mipi_dsi {
	[...]
	panel@0 {
		[...]
		rotation = <90>;
		[...]
	};
};

That works that console output and desktop are rotated but I also get a kernel warning for doing that:
dmesg.log (38.2 KB), timestamp 1.731203.

This thread points out that it is because of a race condition during registration of the connector (as far as I understand it). But the patch to solve this was not accepted until now.

What can I do with the kernel warning? Do I have to worry about it?

Best regards,
Markus

2

Hello Mowlwurf,

which carrier board are you using?

Best Regards,

Matthias

3

Hi @matthias.tx,

I’m using the Verdin Development Board V1.1 with BSP v6.0

Best regards,
Markus

4

Hi @Mowlwurf !

Does the issue always occur?

Have you tried to apply the patch and check the result? Does the patch solve the issue for you?

What you can do is monitor this patch if it is going to be integrated into the Linux Kernel or not (from the link you shared, seems like there is no movement about it since Feb/Mar 2022).

This is a hard question to answer.

The best you can do is to go to the source code, analyze what happens, and how the issue is triggered and what could happen after it.

Best regards,

5

Hi @Mowlwurf !

Do you have any news related to this issue?

Best regards,

6

Hi @henrique.tx ,

I tried to dig into this but this is rocket science for me …

There was some movement in this topic until June '22 ([PATCH v10 1/4] gpu: drm: separate panel orientation property creating and value setting — ARM, OMAP, Xscale Linux Kernel) but again with an open end.

Since the patch isn’t accepted until today I will leave it as it is and live with the warning (I don’t see any negative effects) or try to rotate the screen with weston.

Best regards,
Markus

7

Hi @Mowlwurf

Thanks for the feedback!

Have a great day!