From: tytso@ATHENA.MIT.EDU (Theodore Ts'o) Subject: Re: Makefile, serial problems with 0.99.3 Date: Sat, 16 Jan 1993 03:14:59 GMT
From: kxb@cis.ksu.edu (Karl Buck)
Date: 15 Jan 93 11:58:46 GMT
2. Going from pl2 to pl3 I can suddenly no longer use Seyon or Kermit.
Seyon does not come back with any messages and Kermit gives the error
message "Cannot read character: I/O error".
Anyone else having these problems?
What this means is that Linux failed to detect a serial port at that
address: either because you had AUTO_IRQ enabled, and the irq detection
code failed on your system; or because you have a non-standard uart
which fails the UART detection tests performed by Linux at bootup.
In 0.99pl3, the serial driver is won't allow you to write to a serial
port which it believes is nonexistent, to avoid reported problems of
Linux locking up when in the past when people accidentally opened a
nonexistent port. However, if you *know* that you have a 16450 UART
at port 0x3f8, irq 4, and that should be ttys0, you can use the
setserial command to set this:
setserial /dev/ttys0 port 0x3f8 irq 4 uart 16450
However, if you do this, please be very careful; since if you give the
wrong paramters to setserial, you can lock up your machine. For this
reason, setserial must be run as root.
Please let me know if you need to do this in order to use your serial
ports; the information I will need to debug this is:
* Did you compile your kernel with AUTO_IRQ or not?
What version of the kernel and the serial driver are you
using.
* An exact copy of the kernel bootup messages, especially for
the serial lines.
* What is printed by "setserial /dev/ttys0", where you should
replace /dev/ttys0 by whatever device name which is
giving you trouble.
- Ted