I have a Linux USB HID device (a Hama MCE), and I can read its events manually by reading cat /dev/input/event7
and cat /dev/input/event8
. Whenever I press a key on the device, a few bytes become available for reading with one of the cat
commands above. I have a default installation of Ubuntu Jaunty 64-bit desktop on the machine.
I think I can write a parser to interpret the bytes emitted by the device, or I'll use libhid if it's more convenient.
My questions are:
/usr/local/bin/keydumper /dev/input/event7 /dev/input/event8
(or one command for each /dev/
path) would get run, with the proper /dev/
paths substituted in the command line? Answering my own question based on answers from the Linux USB HID driver developers:
Question 1. and 2.: Do
ioctl(open("/dev/input/event7", O_RDONLY), EVIOCGRAB, 1);
As long as this filehandle is open, the events generated would go only to this filehandle (not to other open()s of the same device or to the system keyboard or mouse event pool). At most one process can hold a successful EVIOCGRAB at a HID device at a time. Lirc can be configured to do an EVIOCGRAB.
Question 3.: Configure udev to start the program once the device is connected.