Linux loads "spidev" module even if spidev.ko.xz file is removed

[dudeiot]

Hi,

I could  enable  "spidev" support  by  armbian-config -> system -> hardware (enable spidev) . Everything worked fine.

However, the original spidev module supports messages only up to 4096 bytes.

I compiled a new version of custom spidev.ko with the 32,768 buffer size.

Then, converted it to spidev.ko.xz  ( xz -v spidev.ko) and replaced the original file under /lib/modules/5.15.85-sunxi/kernel/drivers/spi/spidev.ko.xz 

The  new module works fine when I install it manually:  insmod /lib/modules/5.15.85-sunxi/kernel/drivers/spi/spidev.ko.xz

However, after the reboot the original 4096-byte version of "spidev"  module is loaded magically.

It is loaded even if I  remove the /lib/modules/5.15.85-sunxi/kernel/drivers/spi/spidev.ko.xz file.

I searched through the whole micro-SD partition and cound not find any copy of spidev.ko.xz or spidev.ko

 

Would you please explaine the mystery ?

Thanks in advance

 

 

[Werner]

Providing logs with 

armbianmonitor -u

 helps with troubleshooting and significantly raises chances that issue gets addressed.

[Gunjan Gupta]

17 hours ago, dudeiot said:

Then, converted it to spidev.ko.xz  ( xz -v spidev.ko) and replaced the original file under /lib/modules/5.15.85-sunxi/kernel/drivers/spi/spidev.ko.xz 

In your list of steps, I am not seeing that you ever ran depmod to ensure extraction of updated module deplist and symbols information. Without that kernel will not try to load your module other than you force loading it with insmod.

 

17 hours ago, dudeiot said:

However, after the reboot the original 4096-byte version of "spidev"  module is loaded magically.

It is loaded even if I  remove the /lib/modules/5.15.85-sunxi/kernel/drivers/spi/spidev.ko.xz file.

I searched through the whole micro-SD partition and cound not find any copy of spidev.ko.xz or spidev.ko

Nothing magical about it, The module most likely would also be present inside initrd file and being loaded from there. You never mentioned that you regenerated initrd, so thats a possible explaination

[dudeiot]

Quote

armbianmonitor -u

https://paste.armbian.com/apusitudaq

 

Quote

In your list of steps, I am not seeing that you ever ran depmod 

I did not mention that. However,  I executed

 

depmod -a

sync

reboot

 

It did not help

 

Quote

The module most likely would also be present inside initrd file

Good catch ! If the module is loaded from the initrd  it explains everything.

It seems to solve my problem  it is necessary to change "devspi" module source in Linux source tree and regenerate all images.

Is  there a simple way to generate  uInitrd-5.15.85-sunxi  only?

 

 

Thanks

Edited October 29, 2023 by dudeiot

[Gunjan Gupta]

15 hours ago, dudeiot said:

Is  there a simple way to generate  uInitrd-5.15.85-sunxi  only?

if you want to do it on the device itself, use the following command

 

update-initramfs -u -k all