serial over /dev/ttyu0 does not work.
Stefan Lambrev
stefan.lambrev at sun-fish.com
Sat May 19 12:26:51 UTC 2007
Hello list.
There is a weird situation where my serial connection stoped working.
I have disabled device sio in kernel and replaced it with device uart.
And so dmesg |grep uart is :
uart0: <16550 or compatible> port 0x3f8-0x3ff irq 4 on acpi0
I was expecting to see uart1 too .. but it is not here.
I have: /dev/ttyu0 & /dev/cuau0, also in /etc/ttys I have the following
line:
ttyu0 "/usr/libexec/getty std.9600" vt100 on secure
I have this configuration on other servers too and it works without
problems,
but the main difference that I found is when I use minicom.
I think if I try to open /dev/cuau0 I should see "Device busy" - and on
all other servers where I checked
it does respond with "Device busy" as it is already used, but on this
server I do not!
Also I notice that where the serial is NOT working I have this line in
ps xa:
1653 ?? I 0:00.00 /usr/libexec/getty std.9600 ttyu0
In first moment I thought it is OK to have getty on ttyu0, but what is
this "??" :)
so I checked on the other server and I saw that there is NO getty on
ttyu0 running at all (it is started
when I start minicom from the other side of the serial but then it shows:
99615 u0 Ss+ 0:00.00 /usr/libexec/getty std.9600 ttyu0
and it is stopped when I stop minicom)
Any useful ideas where to look for ? Also switching back from uart to
sio may sound OK, but it needs another restart :(
both machines are using:
uname -srm
FreeBSD 6.2-STABLE amd64
P.S. I'm 100% sure it is not a cable problem as the serial console was
working with device sio 5minutes ago :(
The problem is that with sio the second com port that not work due I/O
range conflicts and uart saved me once so I try
same solution and here.
--
Best Wishes,
Stefan Lambrev
ICQ# 24134177
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