Colibri iMX7 - Disable Display and use pins differently

Hi

I am trying to disable the standard display functionality and use the SODIMM pins differently. If I am booting the Colibri iMX7 module via TFTP/NFS, everything works fine. Unfortunately, if I am booting the exactly same image from the modules eMMC, Linux hangs either just before or after I am able to login on the debug console.

What I have found out up til now is the following:

If I remove (or disable) &lcdif in the device tree (imx7-colibri-aster.dtsi) and/or remove the corresponding pin mapping, the problem occurs.

&lcdif {
	/delete-node/pinctrl-names;
	/delete-node/pinctrl-0;
	status = "disabled";
}

Do you have any idea what might cause this issue? Especially, why it is only occurring if booted from eMMC and not via TFTP/NFS?

Thanks and best regards,
Tonio

Hi Tonio

Could you provide the version of the software of your module?

Linux hangs either just before or after I am able to login on the debug console.

Could you share the serial boot log for eMMC and NFS Boot?

Please share also your kernel .config and all your devicetree changes ( git diff ).

Thanks and best regards,
Jaski

Hi @jaski.tx

It got even stranger now, after I introduced eth0.network to /etc/systemd/network/ the system does not hang anymore booting from eMMC (with exactly the same device tree as before).

Unfortunately I do not have boot log from the hanging boot at hand. But what I can recall is that one of the last entries was the following.

Starting Rebuild Hardware Database

However, I cannot find again the same entry in dmesg, if the system boots properly.

Do you have any idea what this “Rebuild Hardware Database” is at all? And whether it might have triggered the problem?

Thanks and best regards,
Tonio

Hi @jaski.tx

Thanks for your answer.

It works at the moment, which is good. But the issue still leaves a bad feeling. I would of course be more happy, if we could find its cause. But it looks to me as rather hard to debug.

Best regards,

Tonio

Hi @tgsell

Perfect that the module is booting for eMMC Flash.
Regarding the message

: [ OK ] Started Rebuild Hardware Database.

This is a kernel message which appears during the first boot of the module after flashing. But I don’t know more about this.

Is the issue solved now for you?

Best regards,
Jaski

Hi Tonio

Let us discuss this topic, once if happens again and you have more information.

Best regards,
Jaski