My user can't access the serial port

Bogo · Tux's lil' helper Joined: 04 May 2002 Posts: 98

I can't really figure this one out. I've tried chmod a+rw anything in my /dev that looks like it's related to serial and all that, but it doesn't seem to do anything. Only root can access the serial port. I'd assume the solution lies somewhere within devfsd.conf but I don't know too much about that. I tried adding some stuff in there but it didn't seem to do anything. Anyone know what's up? I'm running kernel 2.5.45.
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Carlos · Posted: Tue Feb 18, 2003 4:33 am Post subject:

I don't think it could be the result of devfsd.conf that you can't access your serial ports because the only kind of problems I've heard about resulting from that is the loss of permission changes when the machine is rebooted, for example.

Are you sure you're getting the correct device in /dev? They should be /dev/ttyS0, /dev/ttyS1, etc.
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Bogo · Tux's lil' helper Joined: 04 May 2002 Posts: 98

Yeah I've tried /dev/ttyS0 and /dev/tts/0 and all that.
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Carlos · Posted: Tue Feb 18, 2003 5:09 am Post subject:

What are you using to access the serial port as root? Do you get a "permission denied" error when you try that as another user, afwer you've made the port readable and writable?
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Man must shape his tools lest they shape him.

acidreign · Posted: Tue Feb 18, 2003 5:27 pm Post subject: Assuming that they work as root

Create a new group, call it serialportusers for example.
Edit your devfsd.conf (back it up first) and enter the line

REGISTER ttyS0 PERMISSIONS root.serialportusers rw-rw----

(ttyS0 is the first port, duplicate for ttyS1, ttyS2, etc)

you MUST reboot for this to take effect, killing and devfsd will not work.

After this, add the users to the serialportusers group that you wish to have access to the serial port device.

usermod -G users,serialportusers USERNAME

This will allow users to be able to access the serial port, if its not solving the problem you have a larger issue with your computer.

Bogo · Tux's lil' helper Joined: 04 May 2002 Posts: 98

Maybe I forgot to include something in my kernel or it's just a quirk with 2.5? It's still giving me grief

oh well I guess it's not that important... it's just an inconvenience. Thanks for the help anyways.
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"I know it's only rock and roll but I like it."