Re: [Owfs-developers] Issues with FTDI based USB-Serial dongle & DS2480B

[Stefano M. <mo...@ic...>]

On 30 Sep 2014, at 08:32, Johan Ström <jo...@st...> wrote:

> Hi all,
> 
> picking this up again. Lets summarize the main points:
> 
> * auto-detection can only be relied on for certain pure USB devices
> * auto-detection can not be relied on when "standard" serial bridge chips are used
> * if we can resolve /dev/ttyUSB0 to a particular USB device, we can potentially select a smarter (i.e. improved FTDI) code path instead of regular read/write from the tty device.
> * /dev/ttyUSB0 is not stable, unless explicit devd setup is done.
> * this makes alterantive OWFS device addressing interesting, by specifying USB serial. this would avoid devd all together.

excellent recap. Let me add another remark. 

It seems that Debian, and most of the developers like to run owserver and companion programs as root. Personally I do not like this: on production systems I run owserver without root privileges, so udev/devd is still necessary to set appropriate permissions to /dev files.

Unfortunately this means that with serial emulators some manual setup is needed: inspecting syslog files, noting the device serial number, modifying the udev/devd script. Alternatively owserver and family should drop root privileges after startup.

Stefano