Plymouth: panel-mipi-dbi not loading firmware... and the bin file exists

[robertojguerra]

First of all, thank you Notro for making this driver. It is a foundation for my future projects :)

I am having a problem with loading the bin firmware file for my ili9488 (4" red pcb lcd).

When I have this line in the DTS in my Orange Pi Zero 3, with Linux 6.12 (official Armbian image):
compatible = "panel-mipi-dbi-spi";

The kernel loads the /lib/firmware/panel-mipi-dbi-spi.bin normally, and the LCD starts up normally.
Then I have other X11 problems, and I decided to build my own armbian image (i have done this many times)

Then I copy the same DTS, same bin file to the newly running Armbian OS. Then when I reboot, the LCD remains white :(

Then I check why:
$dmesg|grep panel
...
[ 3.016818] panel-mipi-dbi-spi spi1.0: supply power not found, using dummy regulator
[ 3.017015] panel-mipi-dbi-spi spi1.0: supply io not found, using dummy regulator
[ 3.017250] panel-mipi-dbi-spi spi1.0: Direct firmware load for panel-mipi-dbi-spi.bin failed with error -2
[ 3.017267] panel-mipi-dbi-spi spi1.0: No config file found for compatible 'panel-mipi-dbi-spi' (error=-2)
[ 3.017279] panel-mipi-dbi-spi spi1.0: probe with driver panel-mipi-dbi-spi failed with error -2

I checked that the file exists:
$ ls -l /lib/firmware/pan*
-rw-r--r-- 1 root root 100 ⵢⵓⵍ 1 22:41 /lib/firmware/panel-mipi-dbi-spi.bin
It exists, but the driver didn't use it.

Then, I changed my DTS this way:
compatible = "ili9488","panel-mipi-dbi-spi";
And changed panel-mipi-dbi-spi.bin to ili9488.bin inside the /lib/firmware folder

When I rebooted, the LCD remained white. Then I checked:
$ dmesg|grep panel
[ 2.183425] panel@0 enforce active low on GPIO handle (something that normally appears in all boots)
(the driver is not started by the kernel)

Are there any kernel configurations needed for the panel-mipi-dbi-spi to be able to load a firmware?

In all cases, with LCD working or not, the touch part keeps working (tested with evtest).

(I am now looking at the differences in the linux kernel configuration from the image that works and the image that doesn't work)

THANK YOU!

My DTS file (works in orange pi zero 3 official armbian 6.12 minimal image): attached
ili9488-ads7846.dts.gz

Is there any chance that the files in /lib/firmware are not available at the time that the kernel wants to open it?

Is there a way to postpone the loading of panel-mipi-dbi-spi?

[robertojguerra]

I don't know what was going on before. Now it works: loads the bin file.

UPDATE: the problem was that plymouth, a pkg that gets bundled with xfce.

I uninstalled plymouth, and the LCD started normally again!

It seems to me that plymouth forces panel-mipi-dbi-spi to start at a time when only the initramfs is mounted... so it doesn't see the bin file.

panel-mipi-dbi-spi doesn't have this problem in Raspberry Pi. It is only a problem in Armbian.
In both Raspberry and Armbian, the initramfs does not contain the /lib/firmware/panel-mipi-dbi-spi.bin file

[robertojguerra]

This plymouth issue is so misterious to me. Raspberry OS allows panel-mipi-dpi load the bin file, but Armbian doesn't.

Additional similarities:

• modinfo in both OS show the same information
• There are no references to panel-mipi-dbi in /etc/modules-load.d or /etc/modprobe.d
• In both initrd, I can find panel-mipi-dbi.ko, and there is no bin file

However, when plymouth was installed in armbian

• dmesg|grep panel-mipi-dbi in armbian show that the driver was loaded at 3 seconds, while in raspberry, it loads at 8 seconds
  [ 3.017250] panel-mipi-dbi-spi spi1.0: Direct firmware load for panel-mipi-dbi-spi.bin failed with error -2
  [ 3.017267] panel-mipi-dbi-spi spi1.0: No config file found for compatible 'panel-mipi-dbi-spi' (error=-2)
  [ 3.017279] panel-mipi-dbi-spi spi1.0: probe with driver panel-mipi-dbi-spi failed with error -2

I have learned to extract the initrd into a new folder with unmkinitramfs... I am starting to look into these files

Update: there are no differences in /etc of both initrd's that could control panel-mipi-dbi

update: inspecting dmesg more carefully. In raspberry (with plymouth), the mipi-dbi-spi is loaded AFTER the ext4-fs driver mounts the microSD.
In armbian, with plymouth installed, mipi-dbi-spi is loaded BEFORE.
Without plymouth un-installed, mipi-dbi-spi is loaded AFTER (at 8 seconds)

[robertojguerra]

I fixed the problem by including the bin file in the init ram fs

https://forum.armbian.com/topic/53568-how-to-add-a-specific-single-file-in-the-initrdimg-ideally-automatically-with-update-initramfs/