From: pdh@netcom.com (P D H) Subject: opening and/or reading /dev/ttyS0 gets I/O error Date: Thu, 29 Apr 1993 23:29:21 GMT
I've got 99.9 kernel up and configured for auto-irq detection. Still,
programs are reporting "I/O Error" instantly for all the /dev/ttyS[0-3]
lines. I've tried Kermit and Minicom, and also tried to use "cat" to
read from the port. Attempting to just write results in data going
nowhere. There is no error, and no effect. Trying "atdt" and a number
does not get any dialing.
Would the speed setting be the problem? It seems not, because no data
has actually passed through yet by the time it gets the I/O error.
Hardware configuration:
COM1: 3f8/4: Gateway Telepath modem w/fax
COM2: 2f8/3: Hayes Smartmodem 1200B
COM3: 3e8/5: motherboard serial port COMA:
COM4: 2e8/9: motherboard serial port COMB:
I can, and have, done the setup configuration for COMA and COMB to make
them disabled.
The 2 modems both work under MS-DOS with Telix as the comm program with
no problems.
Are there any more configurations in the kernel that I don't know about?
Do I have to do things like a speed setting ioctl() before attempting to
select()? I am assuming good comm programs do asyncronous I/O with select,
but they might not explicitly do all the needed settings before starting
to do the first select(). I did try changing the speed on Minicom, though
the 38400 speed seems to be absent so I tried 19200.
Is 38400 not supported by Linux? Is that too fast for a serial port
driver?
I'd like to not have to always shutdown Linux to dialup, if you know what
I mean. Maybe I could get rid of DOS altogether sooner then.
-- | Phil Howard, pdh@netcom.com, KA9WGN Spell protection? "1(911)A1" | | Right wing conservative capitalists are out to separate you from your MONEY | | Left wing liberal do gooders are out to separate you from EVERYTHING ELSE!! | +-----------------------------------------------------------------------------+