FTDI USB Serial Device converter disconnects

Bug #122834 reported by Hans Elfberg on 2007-06-28
This bug report is a duplicate of:  Bug #84139: Arduino detected as braille device. Edit Remove
10
Affects Status Importance Assigned to Milestone
linux (Ubuntu)
Undecided
Unassigned
linux-source-2.6.20 (Ubuntu)
Medium
Unassigned

Bug Description

I've just bought an FTDI based USB Serial converter (ID 0403:6001 Future Technology Devices International, Ltd 8-bit FIFO).

Messages from dmesg at the time when the device is connected:
[20462.016000] usb 2-1: new full speed USB device using uhci_hcd and address 11
[20462.268000] usb 2-1: configuration #1 chosen from 1 choice
[20462.268000] ftdi_sio 2-1:1.0: FTDI USB Serial Device converter detected
[20462.268000] drivers/usb/serial/ftdi_sio.c: Detected FT232BM
[20462.268000] usb 2-1: FTDI USB Serial Device converter now attached to ttyUSB0

From the beginning this device disconnected directly after it had been connected. I solved that problem by installing the brltty package. After this fix, however, the device device would instead disconnect after several minutes.

After the device had been automatically disconnected by software, dmesg would show the following error messages:
[19513.820000] drivers/usb/serial/ftdi_sio.c: error from flowcontrol urb
[19513.820000] drivers/usb/serial/ftdi_sio.c: update_mctrl Error from MODEM_CTRL urb: DTR LOW, RTS LOW

I've been looking for a solution to this problem, but so far the best choice i know of is to unload the ehci-hcd module (sudo rmmod ehci-hcd). I'm not sure if this really is a workaround for this problem, and i don't know what other problems it may cause, but the device has not yet disconnected again after i unloaded this module.
/Hans

Hans Elfberg (hans-elfberg) wrote :

I forgot to write that my system is an up to date ubuntu feisty fawn.
/Hans

Davim (davim) wrote :

I have the same problem! And I really need to use the adapter...

Paul Dufresne (paulduf) wrote :

Hi! I am working as a bug triager making sure your bug is complete enough to investigate.
You sure seems to have made a very good job at isolating the right information, but I will request that you add
to this bug the files requested by:
https://wiki.ubuntu.com/KernelTeamBugPolicies
in the minimal information (after the device have disconnected).

I think you should also:
sudo lsusb -v > lsusb.txt
and attached that file (after the device disconnected, and with the ehci-hcd module).

Thanks for taking the time to report bugs!

Hans Elfberg (hans-elfberg) wrote :

I have now updated the Linux kernel from 2.6.20-15-generic. After that it seams to work better, but the same kind of problem is still there. I have generated and attached some information about my system after the device has disconnected.

Thanks for working with this bug!

Changed in linux-source-2.6.20:
importance: Undecided → Medium
Paul Dufresne (paulduf) wrote :

Thanks for giving all the requested information.

As all basic info is there, I asign ubuntu-kernel-team (I would assign ubuntu-kernel-usb, but it is not listed in https://wiki.ubuntu.com/KernelTeamBugPolicies as ok to assign to).
And changing status to Confirmed.

Changed in linux-source-2.6.20:
assignee: dufresnep → ubuntu-kernel-team
status: Incomplete → Confirmed

I have also run into the same problem. If you need any help testing patches let me know.

~$ uname -a
Linux sed192n14 2.6.20-16-generic #2 SMP Thu Jun 7 19:00:28 UTC 2007 x86_64 GNU/Linux

~$ dmesg
[84809.316651] usb 2-5: new full speed USB device using ohci_hcd and address 8
[84809.529248] usb 2-5: configuration #1 chosen from 1 choice
[84809.532249] ftdi_sio 2-5:1.0: FTDI USB Serial Device converter detected
[84809.532257] drivers/usb/serial/ftdi_sio.c: Detected FT232BM
[84809.532433] usb 2-5: FTDI USB Serial Device converter now attached to ttyUSB0
[84810.370480] usb 2-5: usbfs: interface 0 claimed by ftdi_sio while 'brltty' sets config #1
[84810.370636] usb 2-5: usbfs: interface 0 claimed by ftdi_sio while 'brltty' sets config #1
[84810.375398] ftdi_sio ttyUSB0: FTDI USB Serial Device converter now disconnected from ttyUSB0
[84810.375413] ftdi_sio 2-5:1.0: device disconnected
[84815.371119] usb 2-5: usbfs: interface 0 claimed by usbfs while 'brltty' sets config #1
[84815.438750] usb 2-5: usbfs: process 3879 (brltty) did not claim interface 0 before use

~$ sudo lsusb
Password:
Bus 002 Device 001: ID 0000:0000

Christian Reis (kiko) wrote :

Ironically, I have the same symptom, but it is solved if I apt-get remove brltty. With brltty:

[ 7760.720000] usb 2-1: new full speed USB device using uhci_hcd and address 7
[ 7760.900000] usb 2-1: configuration #1 chosen from 1 choice
[ 7760.904000] ftdi_sio 2-1:1.0: FTDI USB Serial Device converter detected
[ 7760.904000] drivers/usb/serial/ftdi_sio.c: Detected FT232BM
[ 7760.904000] usb 2-1: FTDI USB Serial Device converter now attached to ttyUSB0
[ 7764.924000] usb 2-1: usbfs: interface 0 claimed by ftdi_sio while 'brltty' sets config #1
[ 7764.928000] ftdi_sio ttyUSB0: FTDI USB Serial Device converter now disconnected from ttyUSB0
[ 7764.928000] ftdi_sio 2-1:1.0: device disconnected
[ 7784.480000] usb 2-1: USB disconnect, address 7

(The last message is when I actually removed the USB cable, which shows that it disconnects the ftdi_sio device on its own)

Without it:

[78258.424000] usb 2-2: new full speed USB device using uhci_hcd and address 8
[78258.604000] usb 2-2: configuration #1 chosen from 1 choice
[78258.608000] ftdi_sio 2-2:1.0: FTDI USB Serial Device converter detected
[78258.608000] drivers/usb/serial/ftdi_sio.c: Detected FT232BM
[78258.608000] usb 2-2: FTDI USB Serial Device converter now attached to ttyUSB0

Is this not a brltty bug?

Wiktor Wandachowicz (siryes) wrote :
Download full text (6.0 KiB)

Recently I've tried to connect an USB to RS232 adapter. In Ubuntu Edgy 6.10 and in Windows XP the cable worked flawlessly. However, in Ubuntu Feisty 7.04 and in Ubuntu Gutsy 7.10 the system was automatically removing the device, rendering /dev/ttyUSB0 inaccessible. In the end I narrowed it down to brltty package, and specifically one line in /etc/udev/rules.d/85-brltty.rules - details follow.

A quick look in the system log:

$ sudo tail -f /var/log/messages
Sep 14 18:16:51 fine-2 kernel: [ 1409.164000] usb 2-1: new full speed USB device using ohci_hcd and address 3
Sep 14 18:16:51 fine-2 kernel: [ 1409.392000] usb 2-1: configuration #1 chosen from 1 choice
Sep 14 18:16:51 fine-2 kernel: [ 1409.396000] ftdi_sio 2-1:1.0: FTDI USB Serial Device converter detected
Sep 14 18:16:51 fine-2 kernel: [ 1409.396000] drivers/usb/serial/ftdi_sio.c: Detected FT232BM
Sep 14 18:16:51 fine-2 kernel: [ 1409.396000] usb 2-1: FTDI USB Serial Device converter now attached to ttyUSB0
Sep 14 18:16:51 fine-2 kernel: [ 1409.600000] usb 2-1: usbfs: interface 0 claimed by ftdi_sio while 'brltty' sets config #1
Sep 14 18:16:51 fine-2 kernel: [ 1409.604000] ftdi_sio ttyUSB0: FTDI USB Serial Device converter now disconnected from ttyUSB0
Sep 14 18:16:51 fine-2 kernel: [ 1409.604000] ftdi_sio 2-1:1.0: device disconnected
Sep 14 18:18:52 fine-2 kernel: [ 1529.388000] usb 2-1: USB disconnect, address 3

$ lsusb
Bus 003 Device 001: ID 0000:0000
Bus 004 Device 001: ID 0000:0000
Bus 002 Device 006: ID 0403:6001 Future Technology Devices International, Ltd 8-bit FIFO
Bus 002 Device 001: ID 0000:0000
Bus 001 Device 001: ID 0000:0000

The line mentioning 'brltty' looked suspicious, so I did a little search with the exact error message:

Google: "usbfs: interface 0 claimed by ftdi_sio while 'brltty' sets config #1"
* http://www.google.pl/search?hl=pl&q=usbfs%3A+interface+0+claimed+by+ftdi_sio+while+%27brltty%27+sets+config+%231

Interesting results - from what I could tell, all the answers suggested the removal of brltty package.

However, I started noticing something interesting with regard to USB VendorID+ProductId combinations, namely 0403:6001. Device that I posess had exactly the same characteristics. Here are the places describing the same problem:

* http://<email address hidden>/msg56580.html

FTDI UM245R
Vendor Id: 0403
Product Id: 6001

* http://dub.net.nz/hal

FT232BM
/org/freedesktop/Hal/devices/usb_device_403_6001_FTCXA3R6

* https://answers.launchpad.net/ubuntu/+source/gnome-panel/+question/7438

Google: "linux usbserial"
* http://www.google.pl/search?hl=pl&q=linux+usbserial

* http://ftdi-usb-sio.sourceforge.net/

FTDI_SIO
Vendor=0403 ProdID=8372 (ok, this is different)

FT8U232AM
Vendor=0403 ProdID=6001

245 USB <-> Serial
Vendor=0403 ProdID=6001

Finally I checked the brltty package itself, and looked for its udev rules:

$ dpkg -L brltty | grep udev
/etc/udev
/etc/udev/rules.d
/etc/udev/rules.d/85-brltty.rules

Now for the interesting part:

$ grep 6001 /etc/udev/rules.d/85-brltty.rules
SYSFS{idVendor}=="0403", SYSFS{idProduct}=="6001", RUN+="/lib/brltty/brltty.sh -b ht -d usb:"

And to give it more context:

$ gre...

Read more...

Wiktor Wandachowicz (siryes) wrote :

Looks like the problem is well-known since February 2007.

Additional info:
* Bug #84139 - https://bugs.launchpad.net/ubuntu/+source/brltty/+bug/84139
* brltty mailing list:
** http://mielke.cc/pipermail/brltty/2007-February/001812.html
** http://mielke.cc/pipermail/brltty/2007-February/thread.html#1812

The conclusion is that udev rules should be changed. So, awaiting the action from maintainers... A simple, one-liner removal. Please!

Beginning with the Hardy Heron 8.04 development cycle, all open Ubuntu kernel bugs need to be reported against the "linux" kernel package. We are automatically migrating this bug to the new "linux" package. However, development has already began for the upcoming Intrepid Ibex 8.10 release. It would be helpful if you could test the upcoming release and verify if this is still an issue - http://www.ubuntu.com/testing . If the issue still exists, please update this report by changing the Status of the "linux" task from "Incomplete" to "New". We appreciate your patience and understanding as we make this transition. Thanks!

Per a decision made by the Ubuntu Kernel Team, bugs will longer be assigned to the ubuntu-kernel-team in Launchpad as part of the bug triage process. The ubuntu-kernel-team is being unassigned from this bug report. Refer to https://wiki.ubuntu.com/KernelTeamBugPolicies for more information. Thanks.

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