Arch Linux – How to Mount an Unrecognized USB Drive

arch linuxmountusbusb-drive

Using Arch Linux / XFCE, I frequently have problems with USB drives that are not properly mounted. Sometimes they automatically show up in Thunar and I can mount them with one click. However, at other times (it's about fifty/fifty) the drive is just not recognized. I have had this problem with USB External Hard Drives, USB Memory Sticks, and cameras. If the external drive is not recognized, this is the situation:

  • The drive does not show up at fdisk -l at all (it only shows my hard drives)
  • The drive does not appear at /dev/disk
  • The drive DOES appear when running lsusb

So there is some sort of recognition, but I do not understand why, nor do I know how to mount the drives when this happens. I just reboot and hope it works next time, which is clearly not convenient…

UPDATE

When I monitor /var/log/everything.log (no info in syslog), then I see this happen when plugging in the USB:

Dec 14 15:36:32 localhost kernel: [ 6591.042911] usb 1-3: new high speed USB device number 9 using ehci_hcd
Dec 14 15:36:32 localhost mtp-probe: checking bus 1, device 9: "/sys/devices/pci0000:00/0000:00:1d.7/usb1/1-3"
Dec 14 15:36:32 localhost mtp-probe: bus: 1, device: 9 was not an MTP device

This is another requested output:

$udevadm monitor
monitor will print the received events for:
UDEV - the event which udev sends out after rule processing
KERNEL - the kernel uevent

KERNEL[6809.192268] add      /devices/pci0000:00/0000:00:1d.7/usb1/1-3 (usb)
KERNEL[6809.193421] add      /devices/pci0000:00/0000:00:1d.7/usb1/1-3/1-3:1.0 (usb)
UDEV  [6809.299246] add      /devices/pci0000:00/0000:00:1d.7/usb1/1-3 (usb)
UDEV  [6809.306074] add      /devices/pci0000:00/0000:00:1d.7/usb1/1-3/1-3:1.0 (usb)

Best Answer

The problem seems to be a catchall rule in /lib/udev/rules.d/69-libmtp.rules:

# Autoprobe vendor-specific, communication and PTP devices
ENV{ID_MTP_DEVICE}!="1", ENV{MTP_NO_PROBE}!="1", ENV{COLOR_MEASUREMENT_DEVICE}!="1", ENV{libsane_matched}!="yes", ATTR{bDeviceClass}=="00|02|06|ef|ff", PROGRAM="/usr/lib/udev/mtp-probe /sys$env{DEVPATH} $attr{busnum} $attr{devnum}", RESULT=="1", SYMLINK+="libmtp-%k", ENV{ID_MTP_DEVICE}="1", ENV{ID_MEDIA_PLAYER}="1"

Commenting out that line, as shown below, fixed the problem:

# Autoprobe vendor-specific, communication and PTP devices
ENV{ID_MTP_DEVICE}!="1", ENV{MTP_NO_PROBE}!="1", ENV{COLOR_MEASUREMENT_DEVICE}!="1", ENV{libsane_matched}!="yes", ATTR{bDeviceClass}=="00|02|06|ef|ff", PROGRAM="/usr/lib/udev/mtp-probe /sys$env{DEVPATH} $attr{busnum} $attr{devnum}", RESULT=="1", SYMLINK+="libmtp-%k", ENV{ID_MTP_DEVICE}="1", ENV{ID_MEDIA_PLAYER}="1"

In my case, I had to reboot, but there's probably a service that could be restarted instead.

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