Hi all,

I have written a user space program which traps keyboard input from
several input sources using select() function on the /dev/input/eventX
files.

It works nicely, but how can i detect from that same program if user
decides to pull-out a USB connected keyboard or insert another in the
USB port of the embedded Linux system ?

B.Rgds.
Peter
Denmark

> I have written a user space program which traps keyboard input from
> several input sources using select() function on the /dev/input/eventX
> files.
>
> It works nicely, but how can i detect from that same program if user
> decides to pull-out a USB connected keyboard or insert another in the
> USB port of the embedded Linux system ?

Take a look at libusb

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Marco Cavallini
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pweichel <runtime@mail.dk> wrote:

> It works nicely, but how can i detect from that same program if user
> decides to pull-out a USB connected keyboard or insert another in the
> USB port of the embedded Linux system ?

The kernel is running the /sbin/hotplug executable in such a case. Do
whatever yo need to do in this executabole which could be any kind of
executable (bash-script,ELF-binary, etc.). You could simply send a signal
from /sbin/hotplug to your Process which causes it to reopen devices e.g.

Sven

--
"If you continue running Windows, your system may become unstable."
(Windows 95 BSOD)

/me is giggls@ircnet, http://sven.gegg.us/ on the Web

Hi Sven,

Thank you for your input.

The /sbin/hotplug is not default installed on my ARM board running
embedded Linux version 2.6.13.2. Is it a shell program or a binary
executable ?
Can it be cross compiled if binary ?

How can it "signal" my process ?
Can it for example send a message or is it by calling another binary
program ?
Does hotplug tell mee which device i.e. keyboard, barcode scanner or
other USB device has been changed ?

Peter

On Thu, 10 Nov 2005 03:39:42 -0800, pweichel wrote:

> Hi Sven,
>
> Thank you for your input.
>
> The /sbin/hotplug is not default installed on my ARM board running
> embedded Linux version 2.6.13.2. Is it a shell program or a binary
> executable ?
> Can it be cross compiled if binary ?
>
> How can it "signal" my process ?
> Can it for example send a message or is it by calling another binary
> program ?
> Does hotplug tell mee which device i.e. keyboard, barcode scanner or
> other USB device has been changed ?

Ummm... Google for hotplug - 1st hit.

http://linux-hotplug.sourceforge.net/

pweichel <runtime@mail.dk> wrote:

> The /sbin/hotplug is not default installed on my ARM board running
> embedded Linux version 2.6.13.2. Is it a shell program or a binary
> executable ?

Whatever you wand it to be. The Standard Linux hotplug script is written in
bash and is somewhat slow for this reason. Have a look at
http://linux-hotplug.sourceforge.net/ for details.

I use a very small script in one of my applications for detecting USB events
instead of the Standard script.

> How can it "signal" my process ?

Using kill from whithin a shell-script or corresponding system-call from C.

Sven

--
Der "normale Bürger" ist nicht an der TU Dresden und schreibt auch
nicht mit mutt. (Ulli Kuhnle in de.comp.os.unix.discussion)

/me is giggls@ircnet, http://sven.gegg.us/ on the Web