rfcomm blues

CoderMan · 10-19-2009, 05:59 PM

Hi. I posted this thread at official gentoo forums but still no luck there. I was hoping somebody in this crowd might have an answer:

I've got this robotics project where I send commands to the robot via a D-Link DBT-120 bluetooth adapter on the computer side and an eb500 EmbeededBlue bluetooth card on the robot side. This works great on a Fedora box in our lab using rfbind, so we just send and receive characters to /dev/rfcomm* in order to communicate with the robots internal program.

However, I am trying to set up the same thing on my Gentoo netbook (Dell Mini 10v, Intel Atom dual-core 32 bit). However when I try to use the rfcomm created device file, I get this, even running as root:

Code:

$ rfcomm bind rfcomm0
$ cat /dev/rfcomm0 
cat: /dev/rfcomm0: Permission denied

Permissions on the file:

Code:

crw-rw---- 1 root uucp 216, 0 2009-10-16 15:06 /dev/rfcomm0

Nothing changes even if I set the file to root:root.

D-Link adapter is detected:

Code:

$ hcitool dev
Devices:
	hci0	00:1E:58:3F:5C:85

Robot bluetooth card is detected (eb500 is the card, other names are computers):

Code:

$ hcitool scan
Scanning ...
	00:23:6C:BA:C5:19	belmont
	00:0C:84:00:45:A9	eb500
	00:0D:93:11:7B:B3	bootes

So I haven't been able to figure out why this is working on the Fedora box but not on the Gentoo netbook.

Here is the rfcomm config file:

Code:

$ cat /etc/bluetooth/rfcomm.conf
rfcomm0 {
        # Automatically bind the device at startup
        bind no;
#
        # Bluetooth address of the device
        device 00:0C:84:00:45:A9;
#
        # RFCOMM channel for the connection
        channel 1;
#
        # Description of the connection
        comment "Alpha Robot";
}

rfcomm1 {
        # Automatically bind the device at startup
        bind no;
#
        # Bluetooth address of the device
        device 00:0C:84:00:44:2F;
#
        # RFCOMM channel for the connection
        channel 1;
#
        # Description of the connection
        comment "Beta Robot";
}

At the official gentoo forums, someone suggested changing the permissions of the dev file to 777, but that didn't change anything.

unSpawn · 10-19-2009, 06:46 PM

Quote:

Originally Posted by CoderMan

Permissions on the file:

Code:

crw-rw---- 1 root uucp 216, 0 2009-10-16 15:06 /dev/rfcomm0

Nothing changes even if I set the file to root:root. (..) At the official gentoo forums, someone suggested changing the permissions of the dev file to 777, but that didn't change anything.

Isn't /dev/rfcomm* creation governed by HAL or Udev rules?
As in changing DAC perms there?

CoderMan · 10-20-2009, 04:06 PM

I've been looking into this some more. I think the problem is that I am not transmitting the PIN number that is needed. The Fedora box was set up by someone else and I think it uses gnome-passkey or some gnome utility to transmit the pin automatically. My Dell mini uses Xfce4 and so I don't have that installed. Still not sure exactly how to go about fixing this (without installing gnome) but I think I'm headed in the right direction.

unSpawn · 10-20-2009, 05:08 PM

Isn't the default PIN just some file like /etc/bluetooth/pin or a "passkey" statement in /etc/bluetooth/hcid.conf?

CoderMan · 10-20-2009, 05:31 PM

http://forums.gentoo.org/viewtopic-p...4.html#6022104