Sometimes missing splash screen on SPI TFT display

Hi Toradex team,

We have a SPI display (ILI9341 240x320 TFT) attached to a imx6ull (on Iris eval board). And we are using the “fbtft” kernel module for that (see issue SPI TFT display). When we update Torizon core using torizon-core-builder we see the splash screen with a spinner and everything is fine.
But occasionally (especially after power down) the display stays black during boot. And unfortunately the kernel log contains no error.

Do you have an idea why the splash screen is sometimes not showing up?

Best,
Christian

Hi @cgsasse !

Please share the output of tdx-info (Getting Device Information with Tdx-Info | Toradex Developer Center).

Also, could you share how are you powering up the module and the display?

You might be facing a power supply issue.

Best regards,

Hi @henrique.tx ,

This is what tdx-info returns:

Software summary
------------------------------------------------------------
Bootloader:               U-Boot
Kernel version:           5.4.193-5.7.0+git.f5d73fd6e9f8 #1-TorizonCore Fri Jun 24 10:15:32 UTC 2022
Kernel command line:      user_debug=30 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/aac93caa7a9ef69594371e716791c7d392bfaf283c7b4547ff50e4520bfa2126/0
Distro name:              NAME="TorizonCore Upstream"
Distro version:           VERSION_ID=5.7.0-build.17
Hostname:                 colibri-imx6ull-emmc-07324300
------------------------------------------------------------

Hardware info
------------------------------------------------------------
HW model:                 Toradex Colibri iMX6ULL 1GB (eMMC) on Colibri Evaluation Board V3
Toradex version:          0062 V1.1A
Serial number:            07324300
Processor arch:           armv7l
------------------------------------------------------------

We’re using the Iris eval board with a 24V/1A power supply unit.
The display is attached (power and data) to X16 of the Iris board.

Best,
Christian

Hi @cgsasse !

What happens with the display after the boot process? Does it work completely normally?

Are you able to check the power usage of the display (current) during the “good” boot and during the “bad” boot?

Best regards,

Hello @cgsasse ,

We have not received any reply from you.
Have you solved your issue? Do you need additional assistance on our side?

Best regards,
Josep

Hi @josep.tx and @henrique.tx

Sorry for the delay!
Unfortunately our issue is not solved!
But we learned that the supply power is not an issue and that we didn’t ever see any splash screen on the SPI display. What we saw was the shutdown screen!

So we took a journey into building TorizonCore on our own using Yocto. But unfortunately the problem remains that we do not see a splash screen on boot!

What we see from dmesg is that the fbtft kernel module is loaded after more than 20 seconds. And that is way after plymouthd tried to display the splash image!

Can you tell us how we can get the kernel to load the fbtft module much earlier?

Best regards,
Christian

Hi @cgsasse !

Did you build the driver as builtin or as module? As built-in, it will probably start working much sooner.

You can refer to this thread where Jeremias explains how to modify TorizonCore’s kernel configuration in Yocto:

Also, here is Yocto’s documentation (kirstone verison) about Kernel Cache:

https://docs.yoctoproject.org/4.0.8/kernel-dev/advanced.html

Best regards,

Hello @cgsasse ,
Do you have any news on this topic?

Best regards,
Josep