I am using raspbian jessie on raspberry pi 2. recently I wanted to apply PREEMPT-RT patch. I followed steps in that link https://www.raspberrypi.org/documentation/linux/kernel/building.md

After adding this patch, I checked if there are any errors in boot process by typing dmesg I got the following response enter image description here

However everything appears to be working fine except a freezing problem. Raspberry is freezing when running some jobs (for instance: watch -n 1 date) and a wireless adapter is plugged in USB port.

removing wireless adapter, makes no freezing (I was able to keep it running for almost 1 week)

so my questions are

1- What does the error of pcm512x mean.

2- is pcm512x error causing this freezing problem

1 Answer 1


For those who may be interested to know. This error appears when copying zImage of the compiled kernel into the boot directory (for instance doing usr@hostmachine-/linux$ cp /arch/arm/boot/zImage /boot/kernel7.img ).

The right way is to add the kernel as follows

usr@hostmachine-/linux$ ./scripts/mkknlimg ./arch/arm/boot/zImage /boot/kernel7.img

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