[Short Tip] Quickly copy files to Samsung Galaxy S20+ on Fedora 32

Transferring files from a Fedora 32 machine to an Android phone is usually not a problem: plugin in it (via USB), unlock screen, make sure that USB connection is set to file transfer, and open the phone in Nautilus.

However, I recently had to get a new phone, decided to opt for the Samsung Galaxy S20+ – and there I was not able to write files to the device:

rsync: open "/run/user/1000/gvfs/mtp:host=SAMSUNG_SAMSUNG_Android_R58N23ZDCVN/Phone/appdata/2020-04-12_23-38 - foldersync.db" failed: Operation not supported (95)

Note that other phones made no problems so far. And things got even more weird when I realized that I was able to create folders – but not files?!

After the usual tricks (enabling USB debugging, switching cables, etc.) I realized that this might be a special problem with the implementation of mtp by this phone. So instead of using libmtp, wich is used by default by for example gvfs, I tested other mtp implementations – and found simple-mtpfs, which worked like a charm:

$ sudo simple-mtpfs -l
1: SamsungGalaxy models (MTP)
$ sudo simple-mtpfs --device 1 /mnt
# you have to acknowledge access to the phone on the phone screen
# then you have to mount it again
$ sudo simple-mtpfs --device 1 /mnt
$ sudo rsync --verbose --progress --size-only --omit-dir-times --no-perms --recursive --inplace /home/liquidat/backup/ /mnt/Phone/

The performance is good – way better than trying to copy files via gphoto2, btw 😉

Image by Martin Pyško from Pixabay

[Howto] Connecting a USB GSM modem to a KVM guest – USB pass through

With current virtualization technologies it is possible to pass through devices from the host to the guest, calld USB pass through. KVM is no exception here, it even works with a USB GSM modem.

Many of customers I work with are migrating old IT systems and existing servers over to a newer and virtualized infrastructure. That often works without any problems. However, some services do depend on extra hardware like additional PCI cards – or, as in my case, on an external USB GSM modem.

To pass through such a device to the VM guest first the vendor and the product ID must be identified on the VM host:

$ lsusb
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 003 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 004 Device 002: ID 0557:2221 ATEN International Co., Ltd Winbond Hermon
Bus 002 Device 003: ID 12d1:1003 Huawei Technologies Co., Ltd. E220 HSDPA Modem / E230/E270/E870 HSDPA/HSUPA Modem

The last entry shows the mentioned GSM modem, built by Huawei. The interesting numbers are the vendor ID 12d1 and the product ID 1003. THe VM guest is oblivious of the device right now:

$ lsusb
Bus 001 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 001 Device 002: ID 0627:0001 Adomax Technology Co., Ltd 
Bus 001 Device 003: ID 0409:55aa NEC Corp. Hub

Next, the device must be defined in the VM guest XML. This can be done by directly editing the XML file within virsh: $ sudo virsh edit example-server. The command brings up an editor with the content of the XML definition file of the host. The USB device must be added in the device section:

  <devices>
    [...]
    <hostdev mode='subsystem' type='usb' managed='no'>
      <source>
        <vendor id='0x12d1'/>
        <product id='0x1003'/>
      </source>
    </hostdev>
  </devices>

Please note that a leading 0x must be added to the IDs! Save the file, reboot the VM guest, and check if the guest now shows the new device:

$ lsusb
Bus 001 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 001 Device 002: ID 0627:0001 Adomax Technology Co., Ltd 
Bus 001 Device 003: ID 0409:55aa NEC Corp. Hub
Bus 001 Device 004: ID 12d1:1003 Huawei Technologies Co., Ltd. E220 HSDPA Modem / E230/E270/E870 HSDPA/HSUPA Modem

There it is. And the syslog shows that it was properly detected and can now be used in the usual ways, it’s done.

USB Serial support registered for GSM modem (1-port)
option 1-2.1:1.0: GSM modem (1-port) converter detected
usb 1-2.1: GSM modem (1-port) converter now attached to ttyUSB0
option 1-2.1:1.1: GSM modem (1-port) converter detected
usb 1-2.1: GSM modem (1-port) converter now attached to ttyUSB1
usbcore: registered new interface driver option
option: v0.7.2:USB Driver for GSM modems