Re: USB-to-serial adapter no longer working in 8.0-RC1

On Sat, 19 Sep 2009, Hans Petter Selasky wrote:
> On Saturday 19 September 2009 05:40:28 Greg Rivers wrote:
>> Last May, Hans Petter Selasky fixed up the umct driver for 8.0-CURRENT
>> (http://lists.freebsd.org/pipermail/freebsd-current/2009-May/007125.html).
>> After updating to 8.0-RC1 I find that the driver has a new problem.
>>
>> Testing with cu(1) and a modem, I can see by watching the lights on the
>> modem and on the usb-serial adapter that it still asserts DTR and sends
>> and receives characters properly, but no characters reach the terminal.
>> That seems to be the only problem: characters from the attached serial
>> device seem to disappear before reaching whatever program has the serial
>> device open.  But strangely enough, power cycling the modem results in a
>> few "line noise" characters appearing.  Perhaps the driver is no longer
>> responding appropriately to DSR?
>>
>> Any insight or troubleshooting clues would be much appreciated.
>
> Hi,
>
> You need to provide debug output from:
>
> sysctl hw.usb.ucom.debug=15
>
> and
>
> sysctl hw.usb.umct.debug=15
>
> If it exists.
>

hw.usb.umct does not exist, but hw.usb.ucom does.  Here's debug output with
hw.usb.ucom.debug set to 15.  I tested with a modem because it's easy to
interact with.

Attach USB-serial adapter to USB port:
ugen1.2: <Belkin USB PDA Adapter> at usbus1
umct0: <Belkin USB PDA Adapter Belkin Components, class 0/0, rev 1.10/1.02, addr 2> on usbus1
ucom_attach_tty:317: tp = 0xc5644200, unit = 0
ucom_attach_tty:346: ttycreate: U0

Open /dev/cuaU0 via 'cu -l cuaU0 -s 115200 dir':
ucom_open:554: tp = 0xc5644200
ucom_dtr:827: onoff = 1
ucom_line_state:799: on=0x01, off=0x00
ucom_rts:838: onoff = 1
ucom_line_state:799: on=0x02, off=0x00
ucom_break:816: onoff = 0
ucom_line_state:799: on=0x00, off=0x04
ucom_status_change:901:
ucom_param:950: sc = 0xc5433230
ucom_dtr:827: onoff = 1
ucom_line_state:799: on=0x01, off=0x00
ucom_rts:838: onoff = 1
ucom_line_state:799: on=0x02, off=0x00
ucom_cfg_open:520:
ucom_ioctl:653: cmd = 0x402c7413
ucom_ioctl:653: cmd = 0x802c7416
ucom_ioctl:653: cmd = 0x2000740d
ucom_ioctl:653: cmd = 0x402c7413
ucom_ioctl:653: cmd = 0x802c7416
ucom_param:950: sc = 0xc5433230
ucom_ioctl:653: cmd = 0x8004667e
ucom_ioctl:653: cmd = 0x8004667d
ucom_get_data:1064: cnt=0

Type "atz<enter>" (modem resets, responds with "OK"):
ucom_outwakeup:1009: sc = 0xc5433230
ucom_get_data:1064: cnt=1
ucom_get_data:1064: cnt=0
ucom_outwakeup:1009: sc = 0xc5433230
ucom_get_data:1064: cnt=1
ucom_get_data:1064: cnt=0
ucom_outwakeup:1009: sc = 0xc5433230
ucom_get_data:1064: cnt=1
ucom_get_data:1064: cnt=0
ucom_outwakeup:1009: sc = 0xc5433230
ucom_get_data:1064: cnt=1
ucom_get_data:1064: cnt=0
ucom_status_change:901:

Type "atdt<enter>" (modem goes off hook,
finds no dial tone, prints "NO DIALTONE", hangs up):
ucom_outwakeup:1009: sc = 0xc5433230
ucom_get_data:1064: cnt=1
ucom_get_data:1064: cnt=0
ucom_outwakeup:1009: sc = 0xc5433230
ucom_get_data:1064: cnt=1
ucom_get_data:1064: cnt=0
ucom_outwakeup:1009: sc = 0xc5433230
ucom_get_data:1064: cnt=1
ucom_get_data:1064: cnt=0
ucom_outwakeup:1009: sc = 0xc5433230
ucom_get_data:1064: cnt=1
ucom_get_data:1064: cnt=0
ucom_outwakeup:1009: sc = 0xc5433230
ucom_get_data:1064: cnt=1
ucom_get_data:1064: cnt=0
ucom_status_change:901:
last message repeated 2 times

Type "atz<enter>" (modem resets, responds with "OK"):
ucom_outwakeup:1009: sc = 0xc5433230
ucom_get_data:1064: cnt=1
ucom_get_data:1064: cnt=0
ucom_outwakeup:1009: sc = 0xc5433230
ucom_get_data:1064: cnt=1
ucom_get_data:1064: cnt=0
ucom_outwakeup:1009: sc = 0xc5433230
ucom_get_data:1064: cnt=1
ucom_get_data:1064: cnt=0
ucom_outwakeup:1009: sc = 0xc5433230
ucom_get_data:1064: cnt=1
ucom_get_data:1064: cnt=0
ucom_status_change:901:

Type "~." to exit cu:
ucom_ioctl:653: cmd = 0x2000740e
ucom_ioctl:653: cmd = 0x2000740e
ucom_close:623: tp=0xc5644200
ucom_shutdown:446:
ucom_dtr:827: onoff = 0
ucom_line_state:799: on=0x00, off=0x01
ucom_rts:838: onoff = 1
ucom_line_state:799: on=0x02, off=0x00
ucom_cfg_close:605:

Detach USB-serial adapter from USB port:
ugen1.2: <Belkin USB PDA Adapter> at usbus1 (disconnected)
umct0: at uhub0, port 1, addr 2 (disconnected)
ucom_detach_tty:358: sc = 0xc5433230, tp = 0xc5644200
ucom_close:623: tp=0xc5644200
ucom_close:626: tp=0xc5644200 already closed

Note that none of the characters output by the modem made it to cu.  Each
sequence of	ucom_outwakeup:1009: sc = 0xc5433230
 		ucom_get_data:1064: cnt=1
 		ucom_get_data:1064: cnt=0
corresponds to me typing a character.  There are no debug lines
corresponding to characters output by the modem, so they must be getting
dropped prior to reaching the ucom driver.

I also tested with a 8.0-BETA2 system from July 18; it has the same 
problem.  But I know that it was working on 8.0-CURRENT as recently as 
the first week of June.  It still works fine on recent 7.2-STABLE.

-- 
Greg Rivers