MTP Device Issues – Fix File Operations Not Supported on GVFS Mounted MTP Device

gvfslinux-mintmtp

I am running Linux Mint 17.1 64-bit (based on Ubuntu 14.04). Ever since upgrading from Linux Mint 14/Ubuntu 12.10, the Python script I use to sync music to my Walkman has stopped working.

Previously, when I mounted my Walkman, it would automatically show up as the path /run/user/1000/gvfs/WALKMAN/Storage Media and would work like any other file system: I could copy tracks to it, delete tracks from it, etc, all through Python. However, I can't remember if I had to make any changes to get this to happen.

Since upgrading to Linux Mint 17 (and now 17.1), when I mount the Walkman, it shows up as the path /run/user/1000/gvfs/mtp:host=%5Busb%3A002%2C007%5D/Storage Media. Furthermore, when I try to run the same file operations, they now fail. I have discovered that this happens not just through Python, but on the command line as well. For example:

david@MILTON:~$ cp '/data/Music/10SecsWhiteNoise.mp3' '/run/user/1000/gvfs/mtp:host=%5Busb%3A002%2C006%5D/Storage Media/MUSIC'
cp: cannot create regular file ‘/run/user/1000/gvfs/mtp:host=%5Busb%3A002%2C006%5D/Storage Media/MUSIC/10SecsWhiteNoise.mp3’: Operation not supported

I have done some research on this problem, but the most common explanation seems to be that it was formerly solved by this PPA: https://launchpad.net/~langdalepl/+archive/ubuntu/gvfs-mtp

But now, Ubuntu versions since 13.10 contain all these changes so it should no longer be necessary. So why am I still having these errors? I am still able to do file operations on my Walkman through a graphical file manager (Caja, on Linux Mint), just not via the command line.

Best Answer

A guess: you are now actually using MTP for accessing your Walkman, and MTP sucks.

Details

The Operation not supported error could indicate that your Walkman uses an MTP implementation that doesn't support "direct" access. According to http://intr.overt.org/blog/?p=174 this kind of direct access is an Android-specific extension, so it's probably not supported by your Walkman.

As result, you can only use a few selected ways to access files on your Walkman using MTP: I guess everything that reads or writes files in one single operation is supported, while access to selected parts of a file is not supported for these MTP implementations. And it appears that cp and Python always use the latter access method and hence fail.

Possible Workaround

However, you might be able to just replace cp by gvfs-copy. In my tests with a Samsung Android phone (which has a crippled MTP implementation as well) gvfs-copy was able to copy files to the phone where cp failed.

Background

I couldn't find much info about these device-dependent MTP limitations; here are some snippets where the situation is explained somewhat:

https://askubuntu.com/a/284831 https://bugs.launchpad.net/ubuntu/+source/gvfs/+bug/1389001/comments/2 https://bugs.launchpad.net/ubuntu/+source/gvfs/+bug/1157583/comments/1

Why did it work before?

As to why your Walkman was accessible with cp in Mint 14 but not in Mint 17, this might be caused by an internal switch from PTP to MTP as access system. At least that's what I noticed for the Samsung device when switching from Ubuntu 12.04 to 14.04. The phone supports both PTP and MTP, but Ubuntu 12.04 apparently only supports PTP; so that's what was used. Since the new Ubuntu version has built-in support for MTP, this is now used instead.

Actually it might even be the case that your Walkman was previously accessed as USB Mass Storage Device, which is what USB hard disks and flash drives use. Maybe for some reason Linux (or your Walkman) decided that MTP was preferable over Mass Storage access.

You can see the access method used by looking at the URL for the Walkman (in Nautilus, go to the Walkman folder, press Ctrl+L and look at the address bar): for MTP the device is found under eg. mtp://[usb:001,004]/ while for PTP it's something like gphoto2://[usb:001,004]/store_00010001. For Mass Storage access the URL is just a normal path like /media/WALKMAN.

I don't know if MTP has any actual advantages over PTP or Mass Storage, or whether it's possible to switch back to PTP or Mass Storage. Under Linux, both MTP and PTP implementations have their own set of bugs, so it might depend on your use case which one is better. AFAIK Mass Storage is the most desirable option for the user but device support in phones is waning.

Related Solutions

Ubuntu – Mounting an MTP enabled device on Ubuntu 12.04.3 LTS 32-bit

Try out this http://bernaerts.dyndns.org/linux/74-ubuntu/268-ubuntu-automount-any-mtp-device

This guide explains how to easily configure your Ubuntu computer to directly access your Android devices filesystem in MTP mode as soon as you plug it to a USB port. This guide has been completly rewritten to use mtp-detect. It has been tested with a Google Nexus 4 and a Google Nexus 7, but it should work with any other MTP device (Android phone or tablet, MP4 player, ...). It has been done under Ubuntu 12.04 LTS Amd64 but it should work or be easily adapted on many Linux flavours.

How to force a device to be mounted as Mass Media Storage (MMS) rather than Media Transfer Protocol (MTP)

Haven't found a way to make the changes permanent yet, but at least there's a way to manually change drivers:

For example with my sony walkman:

Plug it in and find out its vendor and product id with lsusb:

# lsusb 
Bus 001 Device 003: ID 0402:7675 ALi Corp. 
Bus 001 Device 025: ID 054c:04be Sony Corp. 
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
...

-> so in this case: 054c 04be.

Switch it to usb_storage with:
```
# mtp_switch 054c 04be
```

It should get mounted automatically (on ubuntu at least)

mtp_switch script:

#!/bin/bash

usage()
{
    echo "Usage: mtp_switch vendor_id product_id"
    echo "  switch usb device driver from mtp to usb storage."
    exit 1
}

[ $# = "2" ] || usage

vendor="$1"
product="$2"

die()
{
    echo "$@"
    exit 1
}

find_bus_id()
{
    cd /sys/bus/usb/devices/
    for f in *:* ; do
    if grep -qi "^usb:v${vendor}p${product}" "$f/modalias" 2>/dev/null; then
        echo $f
        return
    fi
    done
}

driver()
{
    readlink "/sys/bus/usb/devices/$bus_id/driver"
}

bus_id=`find_bus_id`
[ -n "$bus_id" ]         || die "couldn't find device"
driver | grep -q 'usbfs' || die "device's driver is not mtp"

cd "/sys/bus/usb/drivers"
echo -n "Unbinding mtp driver ..."
while driver | grep -q usbfs; do
    echo -n "$bus_id" > usbfs/unbind
    sleep 0.5
done
echo ""

echo -n "$bus_id" > usb-storage/bind
echo "Done."