Kategorie: linux-kernel

Udev Sidenotes

Debugging Automatic Debugging Set udev_log=debug in /etc/udev/udev.conf for a persistent change, run udevadm control –log-priority=debug for a temporary change. If you are running systemd, you can find the output in journalctl –follow | grep udev Manual Printing Add RUN+=“/bin/sh -c ‚echo \“hello world\“ > /dev/kmsg'“ to your rules, when the rule is executed you will…

Linux Driver Loading, Binding and Registration

In Linux we have two different types of how drivers find their way into the system. The first is builtin drivers, those drivers are compiled into the kernel image – they are always there and you cannot get rid of them easily (well, you can blacklist them). The other way is the way modules go.…

Linux HID driver hooks

The linux HID subsystem offers kernel driver programmers a whole bunch of hooks to insert custom code before, after and while automatic processing. Those hooks are defined in <linux/hid.h>, unfortunately they aren’t documented very well similarly to the whole loading process of driver modules in Linux.