serial port doesn't work

Asked by Dirk on 2006-11-28

Call me old fashioned, but I still need traditional serial ports. I have three machines with Edgy Ubuntu, the serial port works out of the box on two of them (Compaq Deskpro and Compaq Armada 7800), but not on the third (HP Compaq NC6000 laptop). The NC6000 can do it with COM1 in Windows, though. I am pretty sure that defective hardware and cable problems can be excluded, and the "far side", i.e. the Deskpro, is ok as well.

Right now, I'm just connecting two machines with a null-modem cable. Can anyone help, please? Thanks.

Here is what I get:

{dirk@wanchai}[/home/dirk]ls -l /dev/ttyS*
crw-rw-rw- 1 dialout 4, 64 2006-11-28 03:27 /dev/ttyS0
crw-rw-rw- 1 dialout 4, 65 2006-11-28 03:27 /dev/ttyS1
crw-rw-rw- 1 dialout 4, 66 2006-11-28 03:27 /dev/ttyS2
crw-rw-rw- 1 dialout 4, 67 2006-11-28 03:27 /dev/ttyS3

{dirk@wanchai}[/home/dirk]setserial -a /dev/ttyS0
/dev/ttyS0: No such device

{dirk@wanchai}[/home/dirk]sudo setserial -a /dev/ttyS0
/dev/ttyS0, Line 0, UART: 16550A, Port: 0x03f8, IRQ: 4
Baud_base: 115200, close_delay: 50, divisor: 0
closing_wait: 3000
Flags: spd_normal skip_test

{dirk@wanchai}[/home/dirk]sudo setserial -g /dev/ttyS*
/dev/ttyS0, UART: 16550A, Port: 0x03f8, IRQ: 4
/dev/ttyS1, UART: unknown, Port: 0x02f8, IRQ: 3
/dev/ttyS2, UART: 16550A, Port: 0x03e8, IRQ: 4
/dev/ttyS3, UART: unknown, Port: 0x02e8, IRQ: 3

{dirk@wanchai}[/home/dirk]echo blahblah > /dev/ttyS0
/dev/ttyS0: No such device.

{dirk@wanchai}[/home/dirk]sudo echo blahblah > /dev/ttyS0
/dev/ttyS0: No such device.

{dirk@wanchai}[/home/dirk]dmesg | tail -3
[17204867.876000] ttyS0: LSR safety check engaged!
[17204885.488000] ttyS0: LSR safety check engaged!
[17204901.476000] ttyS0: LSR safety check engaged!
Can anyone help, please? Thanks.Call me old fashioned, but I still need traditional serial ports. I have three machines with Edgy Ubuntu, the serial port works out of the box on two of them (Compaq Deskpro and Compaq Armada 7800), but not on the third (HP Compaq NC6000 laptop). The NC6000 can do it with COM1 in Windows, though. I am pretty sure that defective hardware and cable problems can be excluded, and the "far side", i.e. the Deskpro, is ok as well.

Right now, I'm just connecting two machines with a null-modem cable. Here is what I get:

Quote:
{dirk@wanchai}[/home/dirk]ls -l /dev/ttyS*
crw-rw-rw- 1 dialout 4, 64 2006-11-28 03:27 /dev/ttyS0
crw-rw-rw- 1 dialout 4, 65 2006-11-28 03:27 /dev/ttyS1
crw-rw-rw- 1 dialout 4, 66 2006-11-28 03:27 /dev/ttyS2
crw-rw-rw- 1 dialout 4, 67 2006-11-28 03:27 /dev/ttyS3

{dirk@wanchai}[/home/dirk]setserial -a /dev/ttyS0
/dev/ttyS0: No such device

{dirk@wanchai}[/home/dirk]sudo setserial -a /dev/ttyS0
/dev/ttyS0, Line 0, UART: 16550A, Port: 0x03f8, IRQ: 4
Baud_base: 115200, close_delay: 50, divisor: 0
closing_wait: 3000
Flags: spd_normal skip_test

{dirk@wanchai}[/home/dirk]sudo setserial -g /dev/ttyS*
/dev/ttyS0, UART: 16550A, Port: 0x03f8, IRQ: 4
/dev/ttyS1, UART: unknown, Port: 0x02f8, IRQ: 3
/dev/ttyS2, UART: 16550A, Port: 0x03e8, IRQ: 4
/dev/ttyS3, UART: unknown, Port: 0x02e8, IRQ: 3

{dirk@wanchai}[/home/dirk]echo blahblah > /dev/ttyS0
/dev/ttyS0: No such device.

{dirk@wanchai}[/home/dirk]sudo echo blahblah > /dev/ttyS0
/dev/ttyS0: No such device.

{dirk@wanchai}[/home/dirk]dmesg | tail -3
[17204867.876000] ttyS0: LSR safety check engaged!
[17204885.488000] ttyS0: LSR safety check engaged!
[17204901.476000] ttyS0: LSR safety check engaged!

Question information

Language:
English Edit question
Status:
Solved
For:
Ubuntu Edit question
Assignee:
No assignee Edit question
Solved by:
Dirk
Solved:
2006-12-01
Last query:
2006-12-01
Last reply:
2006-12-01
Alan Pope ㋛ (popey) said : #1

"You're old fashioned"

(you did ask)

Are you in the dialout group?

Here's what happens on my machine.

alan@multivac:~$ ls -l /dev/ttyS*
crw-rw---- 1 root dialout 4, 64 2006-11-27 17:04 /dev/ttyS0
crw-rw---- 1 root dialout 4, 65 2006-11-27 17:04 /dev/ttyS1
crw-rw---- 1 root dialout 4, 66 2006-11-27 17:04 /dev/ttyS2
crw-rw---- 1 root dialout 4, 67 2006-11-27 17:04 /dev/ttyS3

alan@multivac:~$ setserial -a /dev/ttyS0
/dev/ttyS0, Line 0, UART: 16550A, Port: 0x03f8, IRQ: 4
        Baud_base: 115200, close_delay: 50, divisor: 0
        closing_wait: 3000
        Flags: spd_normal skip_test

alan@multivac:~$ groups
alan adm dialout fax cdrom floppy tape audio dip video plugdev lpadmin scanner admin

alan@multivac:~$ echo blahblah > /dev/ttyS0
alan@multivac:~$

Nothing in my dmesg for the serial port.

Dirk (rptq) said : #2

Well, what you see on your machine is what I also get on two others. But still, the third machine (that's actually the most important one) doesn't want to talk on the serial port.

I confirmed that I am member of dialout group. But access rights don't seem to be the reason since I 'chmod 666' the devices and since 'sudo' isn't any more successful than my regular user.

There must be something wrong somewhere else.

Alan Pope ㋛ (popey) said : #3

Serial port enabled in the BIOS?

Dirk (rptq) said : #4

Yes. As I said, the port works fine in Windows. And I just checked the BIOS, the port is still enabled.

Marcantonio (marcantonio) said : #5

I am having the exact same issue with an HP nw8000. I haven't found much yet, but here it is:

    * I had no problems with this in Breezy or Dapper, just Edgy.
    * The LSR error message seems to be a workaround for a
       buggy UART.
    * On boot I noticed this message when udev was starting:

udevd-event[3057]: wait_for_sysfs: waiting for: '/sys/devices/platform/i8042/serio3/serio5/bus' failed

Dirk (rptq) said : #6

Downloaded a Dapper CD and booted from there: serial port works fine.

Can we fix this somehow and get the ports working in Edgy?

Alan Pope ㋛ (popey) said : #7

I would report this as a bug:-

https://bugs.launchpad.net/distros/ubuntu/+source/linux-source-2.6.17/+bugs

Sorry, I can't help further.

Best Dirk (rptq) said : #8

ok, I reported it as a bug:
https://bugs.launchpad.net/distros/ubuntu/+source/linux-source-2.6.17/+bug/74034

As a workaround I'm using a cheapo USB->COM cable. Works ok.