Mailinglist Archive: opensuse-bugs (4653 mails)

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[Bug 575647] cdc-acm shows dev ttyACM0, ttyACM1 on 1st usb plugin, ttyACM1, ttyACM2 on subsequent plugins.
  • From: bugzilla_noreply@xxxxxxxxxx
  • Date: Tue, 2 Feb 2010 23:29:39 +0000
  • Message-id: <20100202232939.9877B24551B@xxxxxxxxxxxxxxxxxxxxxx>
http://bugzilla.novell.com/show_bug.cgi?id=575647

http://bugzilla.novell.com/show_bug.cgi?id=575647#c3


--- Comment #3 from Miles Maybee <miles.maybee@xxxxxxxxx> 2010-02-02 23:29:38
UTC ---
While I'm connected, lsof | grep ACM shows, e.g.:

pppd 23457 root 8u CHR 166,1 0t0 57621
/dev/ttyACM1

Upon unplug, lsof | grep ACM returns nothing.

While connected, ls -l /dev/ttyACM* gives e.g.:

crw-rw---- 1 root dialout 166, 0 2010-02-02 13:53 /dev/ttyACM0
crw-rw---- 1 root dialout 166, 1 2010-02-02 14:26 /dev/ttyACM1
crw-rw---- 1 root dialout 166, 2 2010-02-02 14:25 /dev/ttyACM2

upon unplug it shows:

crw-rw---- 1 root dialout 166, 0 2010-02-02 13:53 /dev/ttyACM0
crw-rw---- 1 root dialout 166, 1 2010-02-02 14:26 /dev/ttyACM1

and so forth... a udev issue perhaps? When replugging, cdc-acm will
not reuse an existing device node, it creates (or accesses) 2 new ones. Upon
unplug, the higher number device node is deleted (even though it isn't the
one being used), but the lower numbered node is not deleted, i.e.,
upon 1st unplug node 0 is not deleted, and cdc-acm uses nodes 1 and 2
upon replug. The second unplug leaves nodes 0 and 1, and 2nd replug generates
nodes 2 and 3, etc ad infinitum.

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