Not at all
In OpenWrt 19.07.3, libudev-fbsd is v20171216-1, size 5.8 KB installed see here
libudev-fbsd_20171216-1_arm_cortex-a9_vfpv3.ipk 5.7 KB Sun Apr 19 09:55:59 2020
In OpenWRT v17.01.6, libudev_3.2-1_arm_cortex-a9_vfpv3.ipk 52.4 KB Sun Jul 22 11:23:17 2018 See here
This is this last version I have downloaded in the router at /root and in my PC
I see something different; The installed version is cortex-a9_vfpv3-d16. The version I tried to install is cortex-a9_vfpv3. Is it important ?
I think this is the reason you can't install the package, opkg thinks the architecture isn't supported. The "-d16" allows less capable routers to install the packages, and I suppose yours is compatible with these packages as well.
If your router's architecture is really arm_cortex-a9_vfpv3, I think you can install libudev by adding this to your opkg.conf (relevant link to architecture change):
arch all 100
arch arm_cortex-a9_vfpv3-d16 200
arch arm_cortex-a9_vfpv3 300
~# cat /proc/cpuinfo
processor : 0
model name : ARMv7 Processor rev 1 (v7l)
BogoMIPS : 1866.00
Features : half thumb fastmult vfp edsp neon vfpv3 tls vfpd32
CPU implementer : 0x41
CPU architecture: 7
CPU variant : 0x4
CPU part : 0xc09
CPU revision : 1
processor : 1
model name : ARMv7 Processor rev 1 (v7l)
BogoMIPS : 1866.00
Features : half thumb fastmult vfp edsp neon vfpv3 tls vfpd32
CPU implementer : 0x41
CPU architecture: 7
CPU variant : 0x4
CPU part : 0xc09
CPU revision : 1
Hardware : Marvell Armada 380/385 (Device Tree)
Revision : 0000
Serial : 0000000000000000
I added
in /etc/opkg.conf
then
~# opkg --force-depends remove libudev-fbsd
Package libudev version 3.2-1 has no valid architecture, ignoring.
Removing package libudev-fbsd from root...
~# opkg update
Downloading http://downloads.openwrt.org/releases/19.07.3/targets/mvebu/cortexa9/packages/Packages.gz
Updated list of available packages in /var/opkg-lists/openwrt_core
Downloading http://downloads.openwrt.org/releases/19.07.3/targets/mvebu/cortexa9/packages/Packages.sig
Signature check passed.
Downloading http://downloads.openwrt.org/releases/19.07.3/targets/mvebu/cortexa9/kmods/4.14.180-1-a92a3f5c5bed2671533484c7ace9d5b5/Packages.gz
Updated list of available packages in /var/opkg-lists/openwrt_kmods
Downloading http://downloads.openwrt.org/releases/19.07.3/targets/mvebu/cortexa9/kmods/4.14.180-1-a92a3f5c5bed2671533484c7ace9d5b5/Packages.sig
Signature check passed.
Downloading http://downloads.openwrt.org/releases/19.07.3/packages/arm_cortex-a9_vfpv3-d16/base/Packages.gz
Updated list of available packages in /var/opkg-lists/openwrt_base
Downloading http://downloads.openwrt.org/releases/19.07.3/packages/arm_cortex-a9_vfpv3-d16/base/Packages.sig
Signature check passed.
Downloading http://downloads.openwrt.org/releases/19.07.3/packages/arm_cortex-a9_vfpv3-d16/luci/Packages.gz
Updated list of available packages in /var/opkg-lists/openwrt_luci
Downloading http://downloads.openwrt.org/releases/19.07.3/packages/arm_cortex-a9_vfpv3-d16/luci/Packages.sig
Signature check passed.
Downloading http://downloads.openwrt.org/releases/19.07.3/packages/arm_cortex-a9_vfpv3-d16/packages/Packages.gz
Updated list of available packages in /var/opkg-lists/openwrt_packages
Downloading http://downloads.openwrt.org/releases/19.07.3/packages/arm_cortex-a9_vfpv3-d16/packages/Packages.sig
Signature check passed.
Downloading http://downloads.openwrt.org/releases/19.07.3/packages/arm_cortex-a9_vfpv3-d16/routing/Packages.gz
Updated list of available packages in /var/opkg-lists/openwrt_routing
Downloading http://downloads.openwrt.org/releases/19.07.3/packages/arm_cortex-a9_vfpv3-d16/routing/Packages.sig
Signature check passed.
Downloading http://downloads.openwrt.org/releases/19.07.3/packages/arm_cortex-a9_vfpv3-d16/telephony/Packages.gz
Updated list of available packages in /var/opkg-lists/openwrt_telephony
Downloading http://downloads.openwrt.org/releases/19.07.3/packages/arm_cortex-a9_vfpv3-d16/telephony/Packages.sig
Signature check passed.
opkg install --force-downgrade libudev_3.2-1_arm_cortex-a9_vfpv3.ipk
Installing libudev (3.2-1) to root...
Configuring libudev.
~# opkg info libudev-fbsd
Package: libudev-fbsd
Version: 20171216-1
Depends: libc, libevdev
Provides: libudev
Conflicts: libudev, eudev, udev
Status: unknown ok not-installed
Section: libs
Architecture: arm_cortex-a9_vfpv3-d16
Size: 5815
Filename: libudev-fbsd_20171216-1_arm_cortex-a9_vfpv3-d16.ipk
Description: small udev shim for FreeBSD/devd (and other non-systemd)
I still have the last version.
In fact there is NO _vfpv3-d16 arch in the release 17.01.6
This is not the good way, I'll go back.
Any other idea?
Could you check what I will do?
I want to download the right libudev pkg; From the releases 17.01.6 I can see the arch
arm_cortex-a7_neon-vfpv4/
but as you said, my arch is
Features : half thumb fastmult vfp edsp neon vfpv3 tls vfpd32
Is it compatible? I'd guess "yes" but now I'll be careful.
Did you remove the package? You need to add these lines to opkg.conf and install the package again:
arch all 100
arch arm_cortex-a9_vfpv3-d16 200
arch arm_cortex-a9_vfpv3 300
When I want to install libudev, it return about libudev-fbsd. Why?
Because it's from your router's standard package arch, if you try to install libudev it'll redirect to the current version, which is just a stub.
Should I modify /etc/opkg.conf the way post 28 and install the way I did in post 30?
Yes, and you also need to run these commands:
opkg update
opkg --force-downgrade install libudev_3.2-1_arm_cortex-a9_vfpv3.ipk
Check if libudev is installed:
opkg info libudev
If it's installed you can remove the stub package:
opkg --force-depends remove libudev-fbsd