Re: [gpsd-users] Disabling hotplugging and manually connecting to device

[Ed W]

On 22/12/2011 03:29, Pris Matic wrote:
> Thanks for the reply. I tried to use gpsdctl, but I ran into an issue 
> when removing a device (ie, gpsdctl remove /dev/ttyUSBx): The device 
> gets removed from gpsd's pool, but I can no longer access the serial 
> port the device belongs to until I physically  reconnect the device. I 
> tried this on two devices... one that uses a Prolific chipset (is an 
> actual GPS), and another that uses an FTDI chipset (is not a GPS). The 
> FTDI chipset is the one that causes the problem. However, using both 
> simple serial port code (C/C++) and a gui based serial port 
> comm/monitor (cutecom), I can connect, talk to and disconnect to 
> either device as many times as I want (before gpsd tries to identify 
> the FTDI device -- once that happens, the port in question is locked, 
> or "busy" until I physically reconnect... even killing gpsd doesn't 
> relinquish the port). Is this a bug? I'm using gpsd 3.3 on Arch Linux, 
> on an x86 machine.

There are quite some kernel bugs relating to serial ports, so check for 
these first.

However, yes, I notice some "oddities" relating to removing devices 
which haven't had all open filehandles on the device closed.  For me 
these are usually visible using "fuser" though and *why* they occur can 
be complex, but killing the relevant processes will always fix things 
for me.

Good luck

Ed W