Calibre 2.51.0 triggers MTP failure with particular device

[mikebw]

On two different computers running stock Ubuntu 15.10, I get identical behavior.

When Calibre is NOT running, plugging in my iRulu X1s tablet running Android 5.1.1 ("Lollipop") works correctly, accessing via MTP and able to see folders and files on both internal and external (SD) storage.

When Calibre 2.51.0 is running, the file manager window showing the contents of the table goes empty if it was open, and new windows open rapidly and briefly show icons for internal and external storage before going empty. A new window opens every second or so until either the device is unplugged or Calibre is shut down.

Here is the debug output produced by Calibre (device serial number redacted):

calibre 2.51  embedded-python: True is64bit: True
Linux-4.2.0-27-generic-x86_64-with-debian-jessie-sid Linux ('64bit', 'ELF')
('Linux', '4.2.0-27-generic', '#32-Ubuntu SMP Fri Jan 22 04:49:08 UTC 2016')
Python 2.7.9
Linux: ('debian', 'jessie/sid', '')
Successfully initialized third party plugins: DeDRM
USB devices on system:
[['0x13d3', '0x5188', '0x814', u'Azurewave', u'USB2.0 UVC HD Webcam',
u'NULL'],
 ['0x1f3a',
  '0x1007',
  '0x233',
  u'USB Developer',
  u'Android',
  u'XXXXXXXXXXXXXXXXXXXX'],
 ['0x3eb', '0x8417', '0x1132', u'Atmel', u'Atmel maXTouch Digitizer', u'']]

No disabled plugins
Looking for devices of type: MTP_DEVICE
Unknown device USBDevice(busnum=2, devnum=16, vendor_id=0x1f3a,
product_id=0x1007, bcd=0x0233, manufacturer=USB Developer,
product=Android, serial=XXXXXXXXXXXXXXXXXXXX) claims to be an MTP device
MTP devices connected:
USBDevice(busnum=2, devnum=16, vendor_id=0x1f3a, product_id=0x1007,
bcd=0x0233, manufacturer=USB Developer, product=Android,
serial=XXXXXXXXXXXXXXXXXXXX)

Trying to open: USBDevice(busnum=2, devnum=16, vendor_id=0x1f3a,
product_id=0x1007, bcd=0x0233, manufacturer=USB Developer,
product=Android, serial=XXXXXXXXXXXXXXXXXXXX)
Opening device failed:
Traceback (most recent call last):
  File "site-packages/calibre/devices/mtp/unix/driver.py", line 147, in
debug_managed_device_detection
  File "site-packages/calibre/devices/mtp/driver.py", line 124, in open
  File "site-packages/calibre/devices/mtp/base.py", line 24, in synchronizer
  File "site-packages/calibre/devices/mtp/unix/driver.py", line 216, in open
OpenFailed: Failed to open USBDevice(busnum=2, devnum=16,
vendor_id=0x1f3a, product_id=0x1007, bcd=0x0233, manufacturer=USB
Developer, product=Android, serial=XXXXXXXXXXXXXXXXXXXX): Error: Unable
to open MTP device with busnum=2 and devnum=16, tried 1 such devices

 
Looking for devices of type: SMART_DEVICE_APP
All IP addresses {'lo': [{'peer': '127.0.0.1', 'netmask': '255.0.0.0',
'addr': '127.0.0.1'}], 'wlan0': [{'netmask': '255.255.255.0', 'addr':
'10.0.0.46', 'broadcast': '10.0.0.255'}]}
No device is connected
 
Looking for devices...
 
Devices possibly connected: None

[kovidgoyal]

On linux (and OS X), you cannot have multiple application trying to connect to a MTP device. Only one application can be connected at a time. So turn off the auto connect in your OS/file manager and you will be fine.

[mikebw]

I've always accessed Android devices from Calibre in USB mass storage mode, and MTP is something with which I have little experience.

It's straightforward to disable auto-mounting in Ubuntu using the documented facility in dconf-editor, but now I cannot get Calibre to see the device under "Connect/Share" and "Connect for folder."

I could likely rig up something in Linux using jmtpfs or a comparable utility, which would look the same as old-style USB mass storage, but I suspect this is not what Calibre expects?

Originally Posted by kovidgoyal

On linux (and OS X), you cannot have multiple application trying to connect to a MTP device. Only one application can be connected at a time. So turn off the auto connect in your OS/file manager and you will be fine.

[theducks]

I don't think Auto mount was what he meant.

You may have an APP that runs when a device is mounted. You need to set that to do Nothing when the device connects

[sometimescasey]

Two years later but just wanted to say thanks to Kovid for taking the time to answer. Drove myself nuts trying to get Calibre to recognize my Kindle, uninstalling and reinstalling various libraries. Turns out the solution was just to unmount the Kindle and restart calibre, derp.

Thank you!!