Bug 7858 - cat to Novatel XU870 (HSDPA) card at /dev/ttyUSB* causes panic
cat to Novatel XU870 (HSDPA) card at /dev/ttyUSB* causes panic
Product: Drivers
Classification: Unclassified
Component: USB
i386 Linux
: P2 normal
Assigned To: Greg Kroah-Hartman
Depends on:
Blocks: USB
  Show dependency treegraph
Reported: 2007-01-21 07:01 UTC by Elliot Mackenzie
Modified: 2007-09-05 06:35 UTC (History)
2 users (show)

See Also:
Kernel Version: 2.6.20-r5
Tree: Mainline
Regression: ---

9400 Kernel config (38.24 KB, text/plain)
2007-01-21 07:07 UTC, Elliot Mackenzie

Description Elliot Mackenzie 2007-01-21 07:01:03 UTC
Most recent kernel where this bug did *NOT* occur: Confirmed in 2.6.18->2.6.20
Distribution: Gentoo, but with vanilla kernel
Hardware Environment: Dell 9400 Laptop, Novatel Merlin XU870 HSDPA/3G
Software Environment: Bare build with 2.6.20 kernel.
Problem Description:
System hangs when writing to USB serial port mapped to the XU870.  

There appear to be six serial ports mapped to this device.

crw-rw---- 1 root tty 188, 0 Jan 21 14:54 /dev/ttyUSB0
crw-rw---- 1 root tty 188, 0 Jan 21 14:54 /dev/ttyUSB1
crw-rw---- 1 root tty 188, 0 Jan 21 14:54 /dev/ttyUSB2
crw-rw---- 1 root tty 188, 0 Jan 21 14:54 /dev/ttyUSB3
crw-rw---- 1 root tty 188, 0 Jan 21 14:54 /dev/ttyUSB4
crw-rw---- 1 root tty 188, 0 Jan 21 14:54 /dev/ttyUSB5

Bus 001 Device 003: ID 1410:1430
(NB: No device description is output in lsusb for this device)

usbcore: registered new interface driver usbserial_generic
drivers/usb/serial/usb-serial.c: USB Serial Driver core
drivers/usb/serial/usb-serial.c: USB Serial support registered for airprime
airprime 1-1.3:1.0: airprime converter detected
usb 1-1.3: airprime converter now attached to ttyUSB0
usb 1-1.3: airprime converter now attached to ttyUSB1
usb 1-1.3: airprime converter now attached to ttyUSB2
airprime 1-1.3:1.1: airprime converter detected
usb 1-1.3: airprime converter now attached to ttyUSB3
usb 1-1.3: airprime converter now attached to ttyUSB4
usb 1-1.3: airprime converter now attached to ttyUSB5
usbcore: registered new interface driver airprime

Steps to reproduce:
modprobe airprime
cat "at+cgdcont=1,\"IP\",\"internet\",\"\",0,0" > /dev/ttyUSB[0..5]
<system hang>
Comment 1 Elliot Mackenzie 2007-01-21 07:02:37 UTC
"System hang", by the way, means the system completely locks up, and the caps
and num-lock lights start flashing.
Comment 2 Elliot Mackenzie 2007-01-21 07:07:32 UTC
Created attachment 10142 [details]
9400 Kernel config
Comment 3 Elliot Mackenzie 2007-01-21 07:23:31 UTC
More information....

If I do this:
cat /dev/ttyUSB0
... then in another term do this:
cat "at....." /dev/ttyUSB0 (as before)

Then it does not crash: I get "OK" as expected.

If I omit reading the USB tty, ie I do not do a cat /dev/ttyUSB0 before the
write, then I get a kernel panic.

Unfortunately I do not have a serial device to capture the panic, however, this
is the part that I can see:

airprime_write_bulk_callbackk+0x7d/0x96 [airprime]
Comment 4 Elliot Mackenzie 2007-01-22 02:15:00 UTC
I have just noticed another (perhaps related?) problem with this device.

If I do this:
`cat /dev/ttyUSB0`

...as before (to avoid the kernel panic), then:
`cat "at+cgdcont=1,\"IP\",\"internet\",\"\",0,0" > /dev/ttyUSB0`

...then sometimes I get this sort of thing on the echo:
"at+cgdcgdcgdcgdcgdcgdcgdcgd" or 
this "at+cgdcontcgdcontcgdcontcgdcontcgdcontcgdcont"  
(ie repeated patterns).  

I'm not convinced this would be a timing issue as the characters echoed back 
are the actual correct characters, save for being repeated incorrectly.  If it 
were timing, I'd be expecting some weird characters coming back, but I see 
only sensible characters repeatedly.

Now if I repeat the above line a few times, sometimes I get a perfect echo, 
followed by an "OK" response from the modem, other times I get the above 
repetition followed by an "ERROR" from the modem.
Comment 5 Natalie Protasevich 2007-06-13 19:11:08 UTC
Can you please try 2.6.22-rc4? - there were multiple fixes in USB/HCD area that went into it.

Comment 6 Natalie Protasevich 2007-08-11 10:55:07 UTC
Elliot - ping..
Also, can you please clarify if the device used to work in 2.6.18?
Comment 7 Elliot Mackenzie 2007-08-13 00:30:03 UTC
Oops, sorry, this one slipped through my mailbox.  I have been testing for two weeks against 2.6.20-16 (ubuntu build, not vanilla), and the device stable and fully functional.

I will try against vanilla 2.6.22+ (gentoo most likely) as soon as I have a minute free (probably later this week as I am current tied to a severity 1 fault and am out of the country for a couple of days).  Hope that's OK.

As for 2.6.18, I don't think so.  From memory I think I had to manually hack the XU870 into the airprime.c to be supported.  The module loaded, but I don't recall having much luck with it even then.

Comment 8 Greg Kroah-Hartman 2007-09-05 06:35:27 UTC
Ok, I'm marking this as fixed.

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