The C Source, Patches and (shudder!) Bugs
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Rene93
Posts: 1
Joined: Sun May 10, 2020 11:45 am

Information USB Hub usb_modeswitch_dispatcher on 2.5.2

Post by Rene93 » Sun May 10, 2020 12:10 pm

Hi Josh,

I am using "Lenovo Thinkpad T450" and a "HP Probook 4520s" with Ubuntu 20.04.
Usb_modeSwitch is per default version 2.5.2. Nothing else installed.

After connecting my ZTE Modem to my Lenovo machine everything work as expexted.
==================================================
USB_ModeSwitch log from Sun May 10 10:10:57 2020

Use global config file: /etc/usb_modeswitch.conf

Raw args from udev: 2-2

Bus ID for device not given by udev.
Trying to determine it from kernel name (2-2) ...
Use top device dir /sys/bus/usb/devices/2-2

USB dir exists: /sys/bus/usb/devices/2-2

SCSI dir exists: /sys/bus/usb/devices/2-2
Warning: SCSI attribute "vendor" not readable.
Warning: SCSI attribute "model" not readable.
Warning: SCSI attribute "rev" not readable.
Use interface /sys/bus/usb/devices/2-2/2-2:1.0
----------------
USB values from sysfs:
idVendor 19d2
idProduct 2000
manufacturer ZTE,Incorporated
product ZTE WCDMA Technologies MSM
serial MF1800ZTED010000
bNumConfigurations 1
bConfigurationValue 1
devnum 5
busnum 2
----------------

==================================================

After connecting my ZTE Modem to my HP machine device no "usb_modeswitch magic" happens.

SB_ModeSwitch log from Sun May 10 11:14:56 2020

Use global config file: /etc/usb_modeswitch.conf

Raw args from udev: 2-1.1

Bus ID for device not given by udev.
Trying to determine it from kernel name (2-1.1) ...
Use top device dir /sys/bus/usb/devices/2-1.1

USB dir exists: /sys/bus/usb/devices/2-1.1

SCSI dir exists: /sys/bus/usb/devices/2-1.1
Warning: SCSI attribute "vendor" not readable.
Warning: SCSI attribute "model" not readable.
Warning: SCSI attribute "rev" not readable.
Check class of first interface ...
Device is in install mode.
No access to interface 8. Exit

==================================================

After many hours of debugging and searching i found these articles...

viewtopic.php?f=4&t=1167
https://forums.opensuse.org/showthread. ... an-USB-hub

So I thought there must be a bug on finding top directory for the device in sysfs (line 104 and above)
https://github.com/trevd/usb-modeswitch ... switch.tcl

But luckily i saw the new release with the rewritten dispatcher...
I installed https://packages.debian.org/de/sid/amd6 ... h/download
And everything is working as expected... (on my HP machine)

Many thanks....

Josh
Site Admin
Posts: 6549
Joined: Sat Nov 03, 2007 12:30 am

Re: Information USB Hub usb_modeswitch_dispatcher on 2.5.2

Post by Josh » Mon May 18, 2020 8:55 pm

When USB device names contain dots, it means that a hub is involved.

usb_modeswitch should handle these cases correctly in the upstream version which is also used by Debian. I don't know about the Ubuntu rewrite of the dispatcher though.
Note that mine is the original and Ubuntu has rewritten it in C - just saying ...

linuxtardis
Posts: 9
Joined: Wed Dec 25, 2019 5:28 pm

Re: Information USB Hub usb_modeswitch_dispatcher on 2.5.2

Post by linuxtardis » Mon Jul 06, 2020 2:20 pm

This looks similar to https://bugs.launchpad.net/ubuntu/+sour ... ug/1866926 - the reported interface 8 is in reality a class number that is incorrectly assigned to a variable representing interface number. This problem should only be present in Ubuntu 20.04. Manually downloading and installing Debian-built packages usb-modeswitch and usb-modeswitch-data should work the problem around, as that removes the C rewrite of the dispatcher.

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