Raspberry Pi 4/5: LinuxCNC 2.9.8 (Trixie) – hal_gpio still not working

[stefantobiasiewicz]

Hello guys,
I tried to start LinuxCNC 2.9.8 (Jan 3, 2026) using the hal_gpio configuration on the Debian Trixie image, and I get the following error:

Debug file information:
Note: Using POSIX realtime
rtapi_app: chip.c:186: gpiod_chip_get_line_offset_from_name: Assertion `chip' failed.
./test.hal:16: waitpid failed /usr/bin/rtapi_app hal_gpio
./test.hal:16: /usr/bin/rtapi_app exited without becoming ready
./test.hal:16: insmod for hal_gpio failed, returned -1
32101
Stopping realtime threads
Unloading hal components
Waited 3 seconds for master.  giving up.
Note: Using POSIX realtime
hal_gpio: not loaded
<commandline>:0: exit value: 255
<commandline>:0: rmmod failed, returned -1

I tested this on Raspberry Pi 4 and Raspberry Pi 5 — the error is the same on both.

Line 16 in the HAL configuration:

loadrt hal_gpio inputs=GPIO16,GPIO19,GPIO20,GPIO21 \
        pullup=GPIO16,GPIO19,GPIO20,GPIO21 \
        invert=GPIO16,GPIO19,GPIO20,GPIO21 \
        outputs=GPIO5,GPIO6,GPIO12,GPIO13,GPIO22,GPIO23,GPIO24,GPIO25

According to the 2.9.8 changelog, this issue should be fixed, but I still cannot run the Trixie image on Raspberry Pi.

[andypugh]

Are you definitely running LinuxCNC 2.9.8? "linuxcnc_info" will tell you.
Do you have libgpiod > 2.0? "gpioinfo -v" will tell you.

[stefantobiasiewicz]

Yep, here is results:

linuxcnc_info

The file:    /tmp/linuxcnc_info.txt
can be posted to a forum or a web site like:
     http://pastebin.com
in order to provide information about the linuxcnc
system and configuration.

VIEWER=gedit
                Date: Sun 11 Jan 12:47:28 CET 2026
            UTC Date: Sun 11 Jan 11:47:28 UTC 2026
        this program: /usr/bin/linuxcnc_info
              uptime: 12:47:28 up 7 min, 1 user, load average: 0.61, 1.05, 0.59
     lsb_release -sa: Debian Debian GNU/Linux 13 (trixie) 13 trixie
            linuxcnc: /usr/bin/linuxcnc
                 pwd: /home/rpi-first-boot-wizard/Downloads
                USER: rpi-first-boot-wizard
             LOGNAME: rpi-first-boot-wizard
                HOME: /home/rpi-first-boot-wizard
              EDITOR: 
              VISUAL: 
            LANGUAGE: 
                TERM: xterm-256color
           COLORTERM: truecolor
             DISPLAY: :0.0
             DESKTOP: xfce
        display size: 1920x1080 pixels (509x286 millimeters)
                PATH: /usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/local/games:/usr/games

uname items:
         nodename -n: raspberrypi
      kernel-name -s: Linux
      kernel-vers -v: #1 SMP PREEMPT Debian 1:6.12.62-1+rpt1 (2025-12-18)
          machine -m: aarch64
        processor -p: unknown
         platform -i: unknown
      oper system -o: GNU/Linux

/proc items:
             cmdline: coherent_pool=1M 8250.nr_uarts=0 snd_bcm2835.enable_headphones=0 cgroup_disable=memory numa_policy=interleave nvme.max_host_mem_size_mb=0 snd_bcm2835.enable_headphones=1 snd_bcm2835.enable_hdmi=1 snd_bcm2835.enable_hdmi=0 numa=fake=2 system_heap.max_order=0 smsc95xx.macaddr=DC:A6:32:40:B6:82 vc_mem.mem_base=0x3ec00000 vc_mem.mem_size=0x40000000 console=ttyS0,115200 console=tty1 root=PARTUUID=3bb13899-02 rootfstype=ext4 fsck.repair=yes rootwait quiet splash plymouth.ignore-serial-consoles cfg80211.ieee80211_regdom=PL
          model name: 
               cores: 
             cpu MHz: 
             parport: 
              serial: 

Versions:
                 gcc: gcc (Debian 14.2.0-19) 14.2.0
              python: Python 3.13.5
                 git: git version 2.47.3
          git commit: NA
                 tcl: 8.6
/usr/bin/linuxcnc_info: line 159: wish: command not found
                  tk: 
               glade: not_in_PATH

linuxcnc_var all:

     LINUXCNCVERSION: 2.9.8
LINUXCNC_AUX_GLADEVCP: /usr/share/linuxcnc/aux_gladevcp
LINUXCNC_AUX_EXAMPLES: /usr/share/linuxcnc/aux_examples
            REALTIME: /usr/lib/linuxcnc/realtime
                 RTS: uspace
          HALLIB_DIR: /usr/share/linuxcnc/hallib
              PYTHON: /usr/bin/python3

dpkg -l '*linuxcnc*':
Desired=Unknown/Install/Remove/Purge/Hold
| Status=Not/Inst/Conf-files/Unpacked/halF-conf/Half-inst/trig-aWait/Trig-pend
|/ Err?=(none)/Reinst-required (Status,Err: uppercase=bad)
||/ Name                Version      Architecture Description
+++-===================-============-============-=====================================================================
un  linuxcnc            <none>       <none>       (no description available)
un  linuxcnc-dev        <none>       <none>       (no description available)
un  linuxcnc-doc        <none>       <none>       (no description available)
ii  linuxcnc-doc-en     1:2.9.8      all          motion controller for CNC machines and robots (English documentation)
un  linuxcnc-doc-es     <none>       <none>       (no description available)
un  linuxcnc-doc-fr     <none>       <none>       (no description available)
un  linuxcnc-sim        <none>       <none>       (no description available)
un  linuxcnc-sim-dev    <none>       <none>       (no description available)
ii  linuxcnc-uspace     1:2.9.8      arm64        motion controller for CNC machines and robots
ii  linuxcnc-uspace-dev 1:2.9.8      arm64        PC based motion controller for real-time Linux


** (gedit:2397): WARNING **: 12:47:28.942: Could not load Peas repository: Typelib file for namespace 'Peas', version '1.0' not found

** (gedit:2397): WARNING **: 12:47:28.942: Could not load PeasGtk repository: Typelib file for namespace 'PeasGtk', version '1.0' not found

And libgpiod:

rpi-first-boot-wizard@raspberrypi:~$ sudo gpioinfo  -v
gpioinfo (libgpiod) v2.2.1
Copyright (C) 2017-2023 Bartosz Golaszewski
License: GPL-2.0-or-later
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.

[andypugh]

This might be the problem:

rpi-first-boot-wizard@raspberrypi:~$ sudo gpioinfo  -v

You seem to be logged in as the config wizard rather than as a real user.

This was a problem with some of the Pi images that they booted into the config wizard but without the required wizard package.

Try "sudo apt-get install piwiz" then reboot. It should (hopefully) ask you to create a proper set account and set up some other things on the system.

Whether that helps or not, I am not sure. But I had a 2.9.7 Trixie Pi here, could not load hal_gpio, then upgraded LinuxCNC to 2.9.8 and then I could load hal_gpio.

[stefantobiasiewicz]

I installed piwiz using
sudo apt-get install piwiz
and after reboot I was asked to create a user account.
This fixed the issue! — after that, LinuxCNC started correctly.

Thanks for the help, but I think this should be fixed in future releases.