I have a fully working (for this part) embedded system based on a rather ancient, vendor-modified, Linux v3.18.29.
To solve other problems I am in the process of upgrading everything to current u-boot/kernel/Buildroot.
Everything seems to work, but I have problems with hot-plugging devices.
I remember I had some problems setting up input handling on the old system, but I can't remember exactly what they were (after several years).
I have full sources and I can successfully rebuild both old and new system, but I could not spot relevant differences (_defconfig's changed enough a simple diff won't give understandable results).
Old system was relying solely on devtmpfs, I tried that and also mdev on new, but apparently mdev is never called (at least it does not log in /dev/mdev.log)
I have UEVENT_HELPER=y, UEVENT_HELPER_PATH=/sbin/hotplug, EVENTFD=y, HAVE_PERF_EVENTS=y, INPUT=y, INPUT_EVDEV=y.
Primary usage of this would be to connect a USB barcode scanner in "keyboard emulation" to system.
In particular I need creation of character device /dev/input/event0
Can someone suggest what I should check/enable/whatever?
Update: A bit of details:
- Hardware is based on a tiny SoM "Vocore2" sporting :
- mips32 cpu (MT7628)
- 128M RAM
- Integrated WiFi b/g/n
- 100baseT Ethernet MAC
- Integrated 5 Port Ethernet
- 16M SPI NOR
- SD card (currently 8G)
- USB2 master
- 3 x Serial (3wire)
- Software is:
- U-Boot (mips-next from git)
- Linux v5.5 (just one patch to have fully working SD)
- Buldroot 2020.02 (plus a few custom packages)
- Application (written in python3)
- Most of basic Unix utilities are provided by Busybox, in particular:
- There is no udevd, substitute is Busybox mdev
0 Answers