Something messing up my serial ports

Something messing up my serial ports

Post by Jon Ear » Sun, 30 Jul 1995 04:00:00



I have a really irritating problem that just popped up out of the blue.  I
have been running my Lionux system now for close to a year, and have survived
various little glitches that have come out of the woodwork.

This one stumps me.

Until now, my modem, slip, ppd, etc have been working perfectly.  Today, I
tried to establish a slip connection to my provider, and nothing but errors
occured.  Same with ppp.  Looking in the syslog, I found this:

Jul 29 13:11:41 freebeer pppd[110]: tcgetattr: I/O error
Jul 29 13:11:53 freebeer dip[111]: DIP: tty: get_state: I/O error

I cannot make any kind of connection out of here via the modem... I have tried
minicom, slip, pp and nothing works.   Now, it gets interesting.  When i exit
linux, and start up Trumpet Winsock, I find that the modem is completely
unresponsive.  I have to reset the machine, or power it off to restore proper
serial port operation under dos/win.  

Aside from adding a second hard drive (modifying fstab accordingly) and
exchanging a Logitech busmouse for a MS serial mouse, I haven't changed a
thing in my Linux setup.

The serial ports are located on a Promise 2300 Plus EIDE card, and are both
16550's (even now, Linux still reports them correctly).

Any advice would be appreciated.

Jon

 
 
 

Something messing up my serial ports

Post by Mark Smi » Tue, 01 Aug 1995 04:00:00


: Aside from adding a second hard drive (modifying fstab accordingly) and
: exchanging a Logitech busmouse for a MS serial mouse, I haven't changed a
: thing in my Linux setup.

I would look at the serial port you setup your mouse on and make sure
they don't conflict IRQs..  Sounds to me like the mouse and the modem
are trying to use the same IRQ..

        If you're using the defaults, cua0 and cua2 (Com1 and com3) both
use IRQ4..  cua1 and cua3 (Com2 and Com4) use IRQ3..  If you're using any
ports that might conflict, the responce would be what you've described..

        Something to test it even further..  Try sending something to the
modem like ATM1A (Attention, Speaker on, Answer) and see if the modem
picks up the line..  If it does, then it REALLY sounds like an IRQ
problem..  If it doesn't then it might be something else..  (IRQ conflicts
only affect incoming data..  All the outgoing data gets there correctly
because it doesn't use IRQs to send data..)

--
        Mark Smith
        PolyCat Support
        x1189

 
 
 

1. Something messing up my serial ports

I have a really irritating problem that just popped up out of the blue.  I
have been running my Lionux system now for close to a year, and have survived
various little glitches that have come out of the woodwork.

This one stumps me.

Until now, my modem, slip, ppd, etc have been working perfectly.  Today, I
tried to establish a slip connection to my provider, and nothing but errors
occured.  Same with ppp.  Looking in the syslog, I found this:

Jul 29 13:11:41 freebeer pppd[110]: tcgetattr: I/O error
Jul 29 13:11:53 freebeer dip[111]: DIP: tty: get_state: I/O error

I cannot make any kind of connection out of here via the modem... I have tried
minicom, slip, pp and nothing works.   Now, it gets interesting.  When i exit
linux, and start up Trumpet Winsock, I find that the modem is completely
unresponsive.  I have to reset the machine, or power it off to restore proper
serial port operation under dos/win.  

Aside from adding a second hard drive (modifying fstab accordingly) and
exchanging a Logitech busmouse for a MS serial mouse, I haven't changed a
thing in my Linux setup.

The serial ports are located on a Promise 2300 Plus EIDE card, and are both
16550's (even now, Linux still reports them correctly).

Any advice would be appreciated.

Jon

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