How to print the log messages very early on the booting process without using a serial connection.

Hello again.

I have recompiled the kernel 14.3-RELEASE after having added the drm subsystem patched for enabling the panfrost driver on the radxa zero 3W,but it freezes during boot with this message :

Warning : Device "fb" is Giant locked and may be deleted before FreeBSD 15.0
VT: Replacing driver "efifb" with new "fb".

and nothing happens anymore :

WhatsApp Image 2025-09-30 at 19.11.26.jpeg



With the kernel 14.2 the panfrost driver works. When I switch from 14.2 to 14.3 the only thing I do is replace the kernel and the modules. The rest of the configuration is the same. I use the same dtb file.

What I would like to know is how print the log messages very early on the booting process. My radxa board does not have the GPIO pins,so I can't use a serial connection. Is there an alternative to it ? I have printed the messages that come from the kernel 14.2 where DRM works and it is able to reach the login prompt. Now I want to print the ones that come from the 14.3 and I want to compare them,trying to understand what could be missing / broken. I don't know what else to do to gather more informations about the reasons why it freezes there.

Thanks.
 
It freezes before to be able to establish the connection to the net. Anyway,I've saved the log messages printed on the screen using my smartphone. I see some errors. Not sure if they are relevant.

 
i'd think that this entirely depends on the U-boot configuration in question. freebsd doesn't come into the equation until after you've loaded a kernel, for one.
 
You can use 40-pin GPIO header. You'll need USB to TTL serial adapter, adapter's TX to 3W's RX pin 10, RX to 3W's pin 8, GND to GND. Good luck 🤞
 
as long as you can still ctrl alt del it is not frozen
it looks like Søren's patches are not in
ethernet does not seem to work, also no scmi
also a dtb with panfrost enabled and panfrost code present will get you a lock or a panic without rk_pmdomain which is not in 14.3
 
as long as you can still ctrl alt del it is not frozen

ctr alt del does not work. I thought it worked. sorry for the confusion.

it looks like Søren's patches are not in
ethernet does not seem to work, also no scmi
also a dtb with panfrost enabled and panfrost code present will get you a lock or a panic without rk_pmdomain which is not in 14.3

mmm I will check better,but I have not posted the full log,but only some pieces...
 
Here there is a video that I have recorded with my smartphone with the log messages showed during the booting of the radxa zero 3W and the kernel 14.3 + panfrost driver :


Where should be placed the files that should be modified ?

a) files, files.arm64, kern.pre.mk, options => sys/conf ;
b) GENERIC-DRM-143 => sys/arm64/conf ;
c) gfp.h => sys/compat/linuxkpi/common/include/linux ;
d) powerdom dir => sys/dev ;
e) rk_grf.c , rk_pmdomain.c => sys/arm64/rockchip ;
f) rockchip,rk3562-power.h , rockchip,rk3576-power.h => sys/contrib/device-tree/include/dt-bindings/power ;
g) rockchip,vop2.h => sys/contrib/device-tree/include/dt-bindings/soc/rockchip,vop2.h ;

The opinion of Jesper : "Perhaps a dtb issue".

I saved on my google drive the files that have been modified :


You make me happy if you check if they are correct. Thanks.
 
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