ArchLinux arm working, but message at startup

[mrechte]

Hello.

This what I get when running the demo on a rpi3 b+ with latest Archlinux :

# ./demo --led-cols=64 -D 1 runtext.ppm
non-existent Revision: Could not determine Pi model
Failed to read revision from /proc/device-tree/system/linux,revision
Unknown Revision: Could not determine Pi model
Suggestion: to slightly improve display update, add
    isolcpus=3
at the end of /boot/cmdline.txt and reboot (see README.md)
Size: 64x32. Hardware gpio mapping: regular
Read image 'runtext.ppm' with 500x32
Press <CTRL-C> to exit and reset LEDs

Note that the demo is running okay. There is no system subdir:

# ls /proc/device-tree/
'#address-cells'   chosen       cpus               leds     model   reserved-memory   soc         timer
 aliases       clocks       framebuffer@3e99a000   memory@0     name    serial-number     __symbols__     wifi-pwrseq
 arm-pmu       compatible   interrupt-parent       memreserve   phy    '#size-cells'      thermal-zones

# uname -a
Linux pi3 6.9.12-2-aarch64-ARCH #1 SMP PREEMPT_DYNAMIC Sat Jul 27 13:48:15 MDT 2024 aarch64 GNU/Linux

[hzeller]

Can you figure out what the equivalent way of finding out on Arch is ?

[mrechte]

Sure:

cat /proc/device-tree/model 
Raspberry Pi 3 Model B Plus Rev 1.4

[hzeller]

That is the human readable form, but there should be a way to read the binary value describing the Pi revision from /proc/cpuinfo or /proc/device-tree/system/linux,revision. Probably would be good if Arch adopted the same device-tree access as the official Pi kernels or provide another way to read the pi revision ( https://www.raspberrypi.com/documentation/computers/raspberry-pi.html#raspberry-pi-revision-codes )

[mrechte]

OK I found this thread on ArchLinux ARM forum