Re: [opensuse] Long standing serial port issue in openSuse

On Wed, 2008-08-27 at 16:17 +0200, Per Jessen wrote:
Roger Oberholtzer wrote:

I would love to know how. The serial settigns (baud rate and all) can,
I think, be determined. But blocking mode is a generic file descriptor
setting that I do not think is reported in /proc.

You can get/set it with fcntl().

As I do. But I would like to see it in /proc as well so I can check it
at will.

One more detail, I run the serial port in canonical mode. So the read
calls return only when there is a complete line of data. Which is how
GPS NMEA records are reported. I am guessing that well tested apps
like PPP do not run the serial port in this mode.

I think I would take a look at how ntp does it - ntp has interface code
for GPS receivers too, maybe they've worked out the right way to do it?

Been there. Their code only reads from the serial port when appropriate.
Whenever it wants to sync times. Otherwise, the serial port is not
accessed and data is dropped. As such, and serial port oddity like this
would go un-noticed. ntp is seldom in a read state.
I, however, read all the time as I need all data all the time.

I have also considered if, but can't see how, a spurious error in the
serial port data that matches a flow control character is received (like
XON) could mess up the flow control. As I save every character that
arrives, I can see that no such character arrives. All data is nice
ASCII 7-bit printable characters.

--
Roger Oberholtzer

OPQ Systems / Ramböll RST

Ramböll Sverige AB
Kapellgränd 7
P.O. Box 4205
SE-102 65 Stockholm, Sweden

Office: Int +46 8-615 60 20
Mobile: Int +46 70-815 1696

And remember:

It is RSofT and there is always something under construction.
It is like talking about large city with all constructions finished.
Not impossible, but very unlikely.


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