No password prompt on ttyACM0

[Sam Noble]

I'm using some Zoom 2985C USB modems (and a few other similar cdc_acm
USB modems) for out-of-band management on my Vyatta routers (Read
"Debian Lenny/Testing Systems").

Previously, (On Vyatta software stack that was largely Lenny from ~May
2008) I was able to use dial-in to these with no more configuration than
installing in the deb for mgetty and adding:
T3:23:respawn:/sbin/mgetty -x0 -s 115200 ttyACM0
to /etc/inittab.
Also I'm only pretty sure I tested this out on my Debian Lenny laptop at
the time.

Recently (On Vyatta software stack that is largely Lenny from January
2009, and this time definately also tested on my current Debian Testing
laptop), I am not able to successfully dial in.

Mgetty picks up just fine, and prompts for a username, but never returns
a password prompt.
As an additional wrinkle, it sometimes works normally ~1 time after a
reboot, though by "works" I mean that I get a password prompt and can
log in. Hovever those shell sessions usually last only for ~10-50 lines
of output and then seem to lock up.

At -x9 debug level, the older systems logs look like this:

02/17 18:21:52 CM0 print welcome banner (/etc/issue.mgetty)
02/17 18:21:52 CM0 getlogname (FIDO AUTO_PPP), read:vyatta[0d]
02/17 18:22:00 CM0 input finished with '\r', setting ICRNL ONLCR
02/17 18:22:00 CM0 tio_get_rs232_lines: status: RTS CTS DSR DTR DCD
02/17 18:22:00 CM0 login: use login config file /etc/mgetty/login.config
02/17 18:22:00 CM0 login: stat('/etc/mgetty/login.config') failed: No such file or directory
02/17 18:22:00 CM0 login: fall back to /bin/login
02/17 18:22:00 CM0 calling login: cmd='/bin/login', argv[]='login vyatta'
02/17 18:22:00 CM0 setenv: 'CALLER_ID=none'
02/17 18:22:00 CM0 setenv: 'CONNECT=115200'
02/17 18:22:00 CM0 setenv: 'DEVICE=ttyACM0'
02/17 18:22:00 ##### data dev=ttyACM0, pid=19074, caller='none', conn='115200', name='', cmd='/bin/login', user='vyatta'

But the problem systems never get to the tio_get_rs232_lines:

02/17 19:20:19 CM0 print welcome banner (/etc/issue.mgetty)
02/17 19:20:19 CM0 getlogname (FIDO AUTO_PPP), read:vyatta[0d]
02/17 19:20:23 CM0 input finished with '\r', setting ICRNL ONLCR
~
~

I'm doing the dialing from minicom, And I've tried using the mgetty
version from the older systems on the new systems, but that seemed to
make no difference. I've also tried replacing the login deb with the one
from the older systems, but that also does not seem to make any
difference.

Any advice would be welcome.
Sam Noble



--
Posted automagically by a mail2news gateway at muc.de e.V.
Please direct questions, flames, donations, etc. to news-***@muc.de

[Gert Doering]

Hi,

Post by Sam Noble
I'm using some Zoom 2985C USB modems (and a few other similar cdc_acm
USB modems) for out-of-band management on my Vyatta routers (Read
"Debian Lenny/Testing Systems").

[..]

Post by Sam Noble
I'm doing the dialing from minicom, And I've tried using the mgetty
version from the older systems on the new systems, but that seemed to
make no difference. I've also tried replacing the login deb with the one
from the older systems, but that also does not seem to make any
difference.

This hints more at problems with the USB tty drivers.

As in "if an application does stupid things like 'query serial lines
status' then just hang, instead of returning useful information" -
otherwise there would be something in the mgetty log.

Is debian using a modified kernel, or "bog standard Linus distribution
kernel"? You might want to try an "off the shelf" kernel...

(I have no debian systems around, so it's hard to test)

gert

[Andreas Barth]

Post by Gert Doering
Hi,

Post by Sam Noble
I'm using some Zoom 2985C USB modems (and a few other similar cdc_acm
USB modems) for out-of-band management on my Vyatta routers (Read
"Debian Lenny/Testing Systems").

[..]

Post by Sam Noble
02/17 18:21:52 CM0 print welcome banner (/etc/issue.mgetty)
02/17 18:21:52 CM0 getlogname (FIDO AUTO_PPP), read:vyatta[0d]
02/17 18:22:00 CM0 input finished with '\r', setting ICRNL ONLCR
02/17 18:22:00 CM0 tio_get_rs232_lines: status: RTS CTS DSR DTR DCD
02/17 18:22:00 CM0 login: use login config file
/etc/mgetty/login.config
02/17 18:22:00 CM0 login: stat('/etc/mgetty/login.config') failed: No
such file or directory
02/17 18:22:00 CM0 login: fall back to /bin/login
02/17 18:22:00 CM0 calling login: cmd='/bin/login', argv[]='login vyatta'
02/17 18:22:00 CM0 setenv: 'CALLER_ID=none'
02/17 18:22:00 CM0 setenv: 'CONNECT=115200'
02/17 18:22:00 CM0 setenv: 'DEVICE=ttyACM0'
02/17 18:22:00 ##### data dev=ttyACM0, pid=19074, caller='none',
conn='115200', name='', cmd='/bin/login', user='vyatta'

[..]

Post by Sam Noble
I'm doing the dialing from minicom, And I've tried using the mgetty
version from the older systems on the new systems, but that seemed to
make no difference. I've also tried replacing the login deb with the one
from the older systems, but that also does not seem to make any
difference.

This hints more at problems with the USB tty drivers.
As in "if an application does stupid things like 'query serial lines
status' then just hang, instead of returning useful information" -
otherwise there would be something in the mgetty log.
Is debian using a modified kernel, or "bog standard Linus distribution
kernel"? You might want to try an "off the shelf" kernel...

Well, there is no real "standard kernel". I would also recommend to
try a few different linux kernel versions (also older ones from
Debian).

I copied the debian kernel mailinglist, perhaps there's some good
input from there.


Cheers,
Andi

--
Posted automagically by a mail2news gateway at muc.de e.V.
Please direct questions, flames, donations, etc. to news-***@muc.de

[Christopher Fowler]

Post by Andreas Barth
Well, there is no real "standard kernel". I would also recommend to
try a few different linux kernel versions (also older ones from
Debian).
I copied the debian kernel mailinglist, perhaps there's some good
input from there.

Is this a 2.4.X kernel? I had the same problem with a Multi-Tech ACM
based USB modem. The
issue is that the ACM tty driver is not finished in 2.4.X kernels. The
tty is treated as raw and there
is no cooked I/O. This is not an issue if you are using ppp perhaps but
if you want access to the CLI
via modem it will not work.

Post by Andreas Barth
Cheers,
Andi

--
Posted automagically by a mail2news gateway at muc.de e.V.
Please direct questions, flames, donations, etc. to news-***@muc.de

[Sam Noble]

Post by Gert Doering
This hints more at problems with the USB tty drivers.
As in "if an application does stupid things like 'query serial lines
status' then just hang, instead of returning useful information" -
otherwise there would be something in the mgetty log.

Thanks very much you are quite correct. It turned out the problem was
only in 2.6.26, so we wound up patching the cdc-acm driver from 2.6.27
into the production kernel, and it's mostly working fine now.

Post by Gert Doering
Well, there is no real "standard kernel". I would also recommend to
try a few different linux kernel versions (also older ones from
Debian).
I copied the debian kernel mailinglist, perhaps there's some good
input from there.

I've got linux-image-2.6.26-1-686 handy, (I was running a vanilla
2.6.26.1 from kernel.org) I'll see if the problem is there too and pass
it on to Debian if so.



--
Posted automagically by a mail2news gateway at muc.de e.V.
Please direct questions, flames, donations, etc. to news-***@muc.de