[poky] usb modeswitch problem with udev

[matti kaasinen]

Hi!
As a reference, if anyone hits this subject:
For the firstly there was wrong information regarding udev versions -
actually udevd versions. Both versions were coming from systemd
installations, so their versions are 219 (fido) / 229 (krogoth). Also
/sbin/udevd is the same binary as /lib/systemd/systemd-udevd. Also there is
no such parameter as monitor in systemd version of udevd. I don't know why
running udevd manually from terminal kind of helped as in fact it did not
if I started it automatically as service (so, another systemd-udevd).
However, realizing that udevd = systemd-udevd gave me correct search
criteria. Similar problem - explanation can be found from
https://bbs.archlinux.org/viewtopic.php?id=199075. So, in short: version of
usb_modeswitch (2.2.0) meta-openembedded currently provides is not
compatible with systemd-udevd version of krogoth and newer.

2016-11-15 12:35 GMT+02:00 matti kaasinen <matti.kaasinen at gmail.com>:

> I have experienced strange behavior how usb_modeswitch works together with
> udev in poky/krogoth installation. In fido they worked fine. Usb_modeswitch
> is same in both installations (2.2.0), udev version different
> udev_182/udev_3.1.5.
>
> 1) I don't get logging even though I enable it from
> /etc/usb_modeswitch.conf
> 2) Modem shows only as mass storage - no mode switching happens
>
> I inserted printouts to /lib/udev/usb_modeswitch script. From these prints
> it shows up that plugging modem triggers:
> exec /usr/sbin/usb_modeswitch_dispatcher --switch-mode /2-1:1.0
>
> command twice, but no switching happens.
>
> 3) If I run modeswitch command (below) manually switching happens
> usb_modeswitch -I -W -c /usr/share/usb_modeswitch/12d1\:14fe
> --default-vendor 12d1 --default-product 14fe --target-product 1506
>
> 4) I run
> udevd monitor
> in order to debug udev events => usb_modeswitch logging starts working and
> also switching starts working.
>
> Debug printing from /lib/udev/usb_modeswitch script shows that operation
> starts identically. However, now also switching proceeds:
>
> after
> exec /usr/sbin/usb_modeswitch_dispatcher --switch-mode /2-1:1.0
>
> commands script gets called twice with parameters below
> --driver-bind /devices/platform/ocp/47400000.usb/47401c00.usb/
> musb-hdrc.1.auto/usb2/2-1/2-1:1.0 12d1/1506/102
>
> following sequence gets repeated twice
> --- START ---
> script gets called three times with following parameters (? = 0,1 and 2)
> --symlink-name /devices/platform/ocp/47400000.usb/47401c00.usb/
> musb-hdrc.1.auto/usb2/2-1/2-1:1.3/ttyUSB2/tty/ttyUSB? 12d1 1506
>
> Which resulted following commands (x and y altering):
> exec usb_modeswitch_dispatcher --symlink-name /devices/platform/ocp/
> 47400000.usb/47401c00.usb/musb-hdrc.1.auto/usb2/2-1/2-1:
> 1.x/ttyUSB0/tty/ttyUSBy
> --- STOP ---
>
> It seems that usb_modeswitch_dispatcher discusses to some udev daemon that
> does not start by default in standard installation of poky/krogoth.
> What daemon could this be? Naturally I could bring up this udevd monitor,
> but I would prefer using the correct one if that exists.
>
> Thanks,
> Matti
>
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