How can I install vcgencmd on Debian system?

Question

I'm running Debian Buster (Not Raspbian / RaspberryPiOS) and need to install the rpi userland in order to get access to vcgencmd.

I've tried the following:

cd /tmp
git clone https://github.com/raspberrypi/userland.git
sudo apt-get install cmake
cd userland
./buildme

This ends around the 5% mark, with many error lines and ultimately the following output:

/tmp/userland/interface/khronos/common/khrn_int_hash_asm.s: Assembler messages:
/tmp/userland/interface/khronos/common/khrn_int_hash_asm.s:36: Error: unknown architecture `armv6'
...
...
...
make[2]: *** [interface/khronos/CMakeFiles/khrn_client.dir/build.make:102: interface/khronos/CMakeFiles/khrn_client.dir/common/khrn_int_hash_asm.s.o] Error 1
make[1]: *** [CMakeFiles/Makefile2:439: interface/khronos/CMakeFiles/khrn_client.dir/all] Error 2
make: *** [Makefile:152: all] Error 2

I'm not sure what the solution to this problem is. The 'unknown architecture' seems like a good tarting point. But, I've no idea what the next move is.

Any suggestions / help would be greatly appreciated.

Answer 1

That github page does refer to the fact that you can specify an architecture as an option to buildme, eg. the 64-bit build would be --aarch64, if you are running 64-bit Debian. Otherwise you would want --arm7l (these are listed at the top of that buildme script as the native, ie. on the Pi, builds).

There are pre-compiled versions in https://github.com/raspberrypi/firmware/tree/master/hardfp/opt/vc -- they may or may not work but worth a try if you can't get the build to fly.

Minor nitpick that /tmp is not a great place to build stuff if it is a tmpfs system (it usually is), because that is actually in RAM. Compiling often requires a fair bit of memory (though the vc lib stuff is I think not that much), so by writing the output to RAM, you are directly reducing the amount of memory available for the ongoing compile processes. Not such a big deal if you have a 4+ GB model, but something to be aware of if you are not already.

It looks like the following is needed to be able to get it to run: LD_LIBRARY_PATH=/opt/vc/lib /opt/vc/bin/vcgencmd

That makes sense. Executables are usually linked to libraries that are separate entities in the file system. There is a default set of paths that are searched for them, much like $PATH works for commands, but the linker (which finds the library components) uses a binary cache which is created from configuration files in /etc. The primary one is ld.so.conf, which sources stuff in /etc/ld.so.conf.d.

I notice in the current64-bit version of RpiOS the VideoCore libs are in conventional places, but in the 32-bit version there is still the /opt/vc, and to inform the linker, there's an /etc/ld.so.conf.d/00-vmcs.conf with one line:

/opt/vc/lib

If that's where you've installed stuff, just duplicate this. It doesn't matter what the file is called, as long as it is in /etc/ld.so.conf.d/ and it contains that line. Also make sure it is only writable by root as this is potentially a very nasty security hole (so owned root.root and with 644 permissions, as non-privileged process do need to read it). Then:

sudo ldconfig

This reads those files and updates the linker cache, so that the VC libs will now be found without explicitly having to set LIBRARY_PATH.

Answer 2

Short answer:

Copying from raspberry pi arm64 image works:

root@rpi4:/home/user# apt-get install wget unzip
root@rpi4:/home/user# wget https://downloads.raspberrypi.org/raspios_lite_arm64/images/raspios_lite_arm64-2021-04-09/2021-03-04-raspios-buster-arm64-lite.zip
root@rpi4:/home/user# unzip 2021-03-04-raspios-buster-arm64-lite.zip
root@rpi4:/home/user# mount -o offset=272629760 2021-03-04-raspios-buster-arm64-lite.img /mnt/
root@rpi4:/home/user# cp /mnt/lib/aarch64-linux-gnu/libvchiq_arm.so.0 /lib/aarch64-linux-gnu/
root@rpi4:/home/user# cp /mnt/lib/aarch64-linux-gnu/libvcos.so.0 /lib/aarch64-linux-gnu/
root@rpi4:/home/user# cp /mnt/usr/bin/vcgencmd /usr/bin/
root@rpi4:/home/user# umount /mnt/
root@rpi4:/home/user# rm 2021-03-04-raspios-buster-arm64-lite.*

Long answer:

After downloading and unpacking the image, the offset of the partition 2 has been determined with fdisk (done on different machine, fdisk on rpi did not worked):

someone@somemachine:~/$ fdisk -l 2021-03-04-raspios-buster-arm64-lite.img 
Disk 2021-03-04-raspios-buster-arm64-lite.img: 1.68 GiB, 1807745024 bytes, 3530752 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0xb941691e

Device                                    Boot  Start     End Sectors  Size Id Type
2021-03-04-raspios-buster-arm64-lite.img1        8192  532479  524288  256M  c W95 FAT32 (LBA)
2021-03-04-raspios-buster-arm64-lite.img2      532480 3530751 2998272  1.4G 83 Linux

532480 (offset of the partition 2) * 512 (units) = 272629760.

After mounting the image, libraries needed by vcgencmd were traced using ldd:

root@rpi4:/home/user# ldd /mnt/usr/bin/vcgencmd
linux-vdso.so.1 (0x0000ffff8125e000)
libvchiq_arm.so.0 => not found
libvcos.so.0 => not found
libpthread.so.0 => /lib/aarch64-linux-gnu/libpthread.so.0 (0x0000ffff811eb000)
libdl.so.2 => /lib/aarch64-linux-gnu/libdl.so.2 (0x0000ffff811d7000)
librt.so.1 => /lib/aarch64-linux-gnu/librt.so.1 (0x0000ffff811bf000)
libc.so.6 => /lib/aarch64-linux-gnu/libc.so.6 (0x0000ffff8104d000)
/lib/ld-linux-aarch64.so.1 (0x0000ffff81230000)

Thanks to user130167 for his initial idea.

Answer 3

My solution to the problem copy it over from the 64 bit image of the Raspian, now Rasberry Pi OS I used the 2020-05-27-raspios-buster-arm64.img to do this a simple straight forward copy of the files required for it to work.

root@zeus-H370M-DS3H:~#  mkdir /tmp/cardroot
root@zeus-H370M-DS3H:~# mount /dev/sde2 /tmp/cardroot

After seeing this I was almost certain it would work.

zeus@zeus-H370M-DS3H:~$ file /tmp/cardroot/opt/vc/bin/vcgencmd
vcgencmd: ELF 64-bit LSB pie executable, ARM aarch64, version 1 (SYSV), dynamically linked, interpreter /lib/ld-linux-aarch64.so.1, for GNU/Linux 3.7.0, BuildID[sha1]=a22f9bd0844d3be74cd9dbd74dd86b6dd3196f7e, stripped
root@buster-raspi:~# file /usr/bin/dd 
/usr/bin/dd: ELF 64-bit LSB pie executable, ARM aarch64, version 1 (SYSV), dynamically linked, interpreter /lib/ld-linux-aarch64.so.1, for GNU/Linux 3.7.0, BuildID[sha1]=aa90bcf288d1293ca8980145095ba1dfba8e9b16, stripped

So I copied it over with rsync to my Pi and tried it.

root@buster-raspi:~# rsync -avP [email protected]:/tmp/cardroot/usr/bin/vcgencmd .
root@buster-raspi:~# ./vcgencmd temp
./vcgencmd: error while loading shared libraries: libvchiq_arm.so.0: cannot open shared object file: No such file or directory

To find the missing files.

root@buster-raspi:~# ldd vcgencmd
linux-vdso.so.1 (0x0000ffff8125e000)
libvchiq_arm.so.0 => not found
libvcos.so.0 => not found
libpthread.so.0 => /lib/aarch64-linux-gnu/libpthread.so.0 (0x0000ffff811eb000)
libdl.so.2 => /lib/aarch64-linux-gnu/libdl.so.2 (0x0000ffff811d7000)
librt.so.1 => /lib/aarch64-linux-gnu/librt.so.1 (0x0000ffff811bf000)
libc.so.6 => /lib/aarch64-linux-gnu/libc.so.6 (0x0000ffff8104d000)
/lib/ld-linux-aarch64.so.1 (0x0000ffff81230000)

root@zeus-H370M-DS3H:/home/zeus/qemu_vms# find /tmp/cardroot/ -name libvcos.so.0
/tmp/cardroot/usr/lib/aarch64-linux-gnu/libvcos.so.0
root@zeus-H370M-DS3H:/home/zeus/qemu_vms# find /tmp/cardroot/ -name libvchiq_arm.so.0 
/tmp/cardroot/usr/lib/aarch64-linux-gnu/libvchiq_arm.so.0

To copy them over into the proper places.

root@buster-raspi:~# rsync -avP [email protected]:/tmp/cardroot/usr/lib/aarch64-linux-gnu/libvcos.so.0 /usr/lib/aarch64-linux-gnu/
root@buster-raspi:~# rsync -avP [email protected]:/tmp/cardroot/usr/lib/aarch64-linux-gnu/libvchiq_arm.so.0 /usr/lib/aarch64-linux-gnu/

Test again to see if it worked.

root@buster-raspi:~# ./vcgencmd measure_temp
temp=49.0'C

Success so copy it to the place it was on the Raspian.

root@buster-raspi:~# mv vcgencmd /usr/bin/
root@buster-raspi:~# which vcgencmd
/usr/bin/vcgencmd

root@buster-raspi:~# cat /etc/debian_version 
10.8
root@buster-raspi:~# uname -a
Linux buster-raspi 5.9.0-0.bpo.5-arm64 #1 SMP Debian 5.9.15-1~bpo10+1 (2020-12-31) aarch64 GNU/Linux

I spent hours more time searching to find this solution and this page. Than the five minutes it actually took once I clued in and had the thought, hey it is based on Buster, perhaps it will work with a copy of it from their system. Sure enough it did, so for anyone finding this is the future who want to know how to do it give it a try.