Re: Recommendations for a serial port card you can actually BUY?

On Sun, Oct 08, 2006 at 04:14:44PM +0200, Matthias Andree wrote:
Karl Denninger <karl@xxxxxxxxxxxxx> writes:

Uh, if you unplug a working serial device's USB cable, you've got bigger
problems :)

So you think? USB is hotplug, and it doesn't have to be a port in use
that you're unplugging.

I realize that but my point is that if you unplug a serial port that has a
process connected to it you're going to yank its file descriptor out from
under it, and it will not be pleased about that!

If you plug and unplug ONLY ONE, it should ID in the same place, since
there's a "hole". If you plug / unplug more than one, I can live with the
penalty being a required reboot. After all, these are NOT supposed to be
tampered with while the machine is running!

OK, that makes things easier.

Perhaps un-/reloading the kernel driver modules (if compiled as module)
is sufficient anyways -- the module will probably reprobe everything upon
reload; OTOH you can check usbd and devd and things if you can pin
devices to certain ordering.

I'm likely going to have a shell script that runs at boot and creates a
"local device" directory with symlinks to the ucom ports involved, based on
their physical location. This way Device #1 that is connected to USB Serial
Adapter #1 can always open /ldev/usb-serial1 and GET the first USB serial
device (plugged into the first physical USB port), no matter in what order
they identify.

--
--
Karl Denninger (karl@xxxxxxxxxxxxx) Internet Consultant & Kids Rights Activist
http://www.denninger.net My home on the net - links to everything I do!
http://scubaforum.org Your UNCENSORED place to talk about DIVING!
http://genesis3.blogspot.com Musings Of A Sentient Mind


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