hook and stop /dev/input/event
lazarus / 32-Linux

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guest59697 · 2018-06-01 08:14

hello Thaddy,
hello FPC enthusiasts,

please a low level question:

I have a touchscreen linux embedded,
I don't have the source of the drivers,
I know that the driver maps over /dev/input/event4 -> and the events
are forwarded/emulated to  -> /dev/mouse1
I need to be able to stop/inhibit the event4 event bubbling, so
stopping the touchscreen, and reenable it without change the config of
X, and without exit from the X session.
Do you know if a HOOK api or similar can be used to STOP/RESTART
/dev/input/event4 globally, for the whole system/users?
Thank you.
Roberto.

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Thaddy · 2018-06-01 08:36

Hi Roberto, only with sudo rights. It also depends on the system. Btw
How are you doing? Haven't spoken to you in a long time.
Technically you should be able to start and stop the device w/o
affecting the X session(s)

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guest59697 · 2018-06-01 09:43

hello,

well, I'm very busy, although this summer I'll try to give to this fpc
community a little layer for a intel mem manager (parallel).

Look, using chmod, setting no permission at all to /dev/input/event
doesn't stop it (probably if it is already open by another task, does
nothing, affecting only the next open's)

Any idea? Maybe using mmap function?

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sash · 2018-06-08 20:16

Hello, I think you can disable device in udev rules
Also I suppose you don't have to. Grab (open exclusively) device file
with Code: C  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i ioctl(fd,
EVIOCGRAB, ...); so events would be visible to your app only.