/dev/ttyU0 - block at open

[Ed Schouten]

Ruslan,

* Hans Petter Selasky <hselasky at c2i.net> wrote:
> This is not directly related to USB, but rather TTY.
> 
> Ed, any clues?
> 
> --HPS
> 
> On Monday 04 October 2010 12:06:41 Ruslan Bukin wrote:
> > Hi!
> > 
> > I am using u3g driver for Gobi 2000 QDL device.
> > The open ("/dev/ttyU0", O_RDWR) does not return anything,
> > But it returns immediately with only O_NONBLOCK or O_NDELAY flags.
> > 
> > is it normal behavior or not?
> > 
> > The device is answering for commands normally in non-block state,
> > but only returns error when I try to write firmware to it.
> > 
> > I think may be the problem is in block/non-block modes.

What kind of cable do you have connected to it? Does it have the carried
detect (DCD) line properly wired up? If not, the behaviour should be
okay, since CLOCAL is turned off by default. If you're not interested in
any carrier, you should open it with O_NONBLOCK.

-- 
 Ed Schouten <ed at 80386.nl>
 WWW: http://80386.nl/
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