[lkml]   [2009]   [Jul]   [27]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
    SubjectRe: [Bisected] [Bug #13821] Replugging USB serial converter uses new device node
    Alan Stern <> writes:

    > On Mon, 27 Jul 2009, Carlos R. Mafra wrote:
    >> On Sun 26.Jul'09 at 22:28:27 +0200, Rafael J. Wysocki wrote:
    >>> Bug-Entry :
    >>> Subject : Replugging USB serial converter uses new device node
    >>> Submitter : Ferenc Wagner <>
    >>> Date : 2009-07-18 20:04 (9 days old)
    >>> References :
    >> I was scanning the regressions list and noticed that I could reproduce
    >> this bug.
    >> So I bisected it to commit 335f8514f200e63d689113d29cb7253a5c282967
    >> ("tty: Bring the usb tty port structure into more use"), from Alan
    >> Cox.
    >> I did not double check if reverting it from -rc4 fixes the issue,
    >> but I noticed that this patch touches drivers/usb/serial/option.c, which
    >> is the driver I used to test this problem.
    >> If there is anything else I can do (give more info, test patches etc),
    >> please let me know.
    > Are you certain this really is a regression? Under 2.6.30 and 2.6.27
    > the same thing happened if I unplugged a USB serial device while it was
    > in use.

    My original report is about unplugging the USB servial device *after*
    using it.

    > Can you check whether the device is still being used when you unplug
    > it? For instance, is there still a pppd process trying to communicate
    > with the device?

    I checked and rechecked that the pppd process is already dead by the
    time I unplug the device. However, the minor number did not increase
    if I unplugged the device without using it beforehand, as expected.

    > In short, it seems likely that this is not new behavior but rather the
    > way usb-serial has worked all along.

    I didn't experience this problem with 2.6.30: my ppp script was
    hardwired to use ttyUSB0 and it always worked. Now with 2.6.31-rc3 it
    does not, as the device node keeps changing.

    I'll test this with opening ttyUSB directly from the shell, instead of
    via pppd, and report back whether it makes a difference.

     \ /
      Last update: 2009-07-27 17:55    [W:0.023 / U:235.476 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site