[Bug 1087519] Re: Serial port ttyS4 doesn't work in 12.04
The fact that the _devicenode_ exists does not necessarely mean that it is allocated in the kernel. So /dev/ttyS4 may show up with ls but may fail when you try to use it. Check CONFIG_SERIAL_8250_RUNTIME_UARTS in your kernel config file. Most likely place is in /boot. The user who is to use a serial port should be in the 'dialout' group. Remember that you need to logout/login to make changes in this area effective. Kees -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1087519 Title: Serial port ttyS4 doesn't work in 12.04 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+bug/1087519/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 1087519] Re: Serial port ttyS4 doesn't work in 12.04
For one, check that your kernel support registration of more than 4 ports if you want to use /dev/ttyS4. The standard config is set to 4. In the case that it tells you port is in use, check for a dangling lock file. cu will create a lock in order to prevent double access. 'lsof' may help you to find if an application is accessing the port (too). dmesg may reveal how many serial ports are allocated during boot. Kees -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1087519 Title: Serial port ttyS4 doesn't work in 12.04 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+bug/1087519/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 1087519] Re: Serial port ttyS4 doesn't work in 12.04
Finally 'strace -f -ff -o /tmp/APP application +args is invaluable with solving problems. less /tmp/APP* will show you all system calls, loads , accesses and so. Multiple APP* files may mean that the main application forked or multi- threaded. While looking with 'less' search for 'open' calls and look return status. Kees -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1087519 Title: Serial port ttyS4 doesn't work in 12.04 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+bug/1087519/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
