Dear Linux USB experts, I noticed that a device (Garmin Foretrex 601, firmware version 2.80) that is supposed to present itself as USB mass storage, does not work on Linux. After being connected, the device does show up in the output of lsusb (ID 091e:0003): $ lsusb Bus 002 Device 002: ID 8087:0024 Intel Corp. Integrated Rate Matching Hub Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub (...) Bus 001 Device 003: ID 17ef:100a Lenovo ThinkPad Mini Dock Plus Series 3 Bus 001 Device 008: ID 091e:0003 Garmin International GPS (various models) Bus 001 Device 002: ID 8087:0024 Intel Corp. Integrated Rate Matching Hub Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub But it does not become available for mounting as USB mass storage devices normally. Moreover, the device itself freezes completely. It is not even possible to switch it off, so that the batteries must be removed. I verified that this problem exists on several machines from different manufacturers running different Linux versions, including my main machine, a Thinkpad X220 $ uname -a Linux abc 4.17.0-3-amd64 #1 SMP Debian 4.17.17-1 (2018-08-18) x86_64 GNU/Linux However, the same device was accessible as USB mass storage one MacOS and one Windows machine that I tried. Moreover, if I plug it into my machine before Linux boots (for example while Grub runs), the device does not freeze. So it seems to me that the problem could be specific to the Linux USB stack. Another symptom that I noticed is that 'lsusb -v' freezes, with the last line it outputs being Bus 001 Device 008: ID 091e:0003 Garmin International GPS (various models) Even 'killall -9 lsusb' does not terminate it. The kernel module garmin_usb that sometimes causes problems is blacklisted and not loaded. Are such problems (USB mass storage devices not working) known or even common? I can well imagine that the culprit is the Garmin device, but it seems that there might be also a problem at the Linux side, since the freezing of lsusb probably should not happen even with a malfunctioning device. I would be grateful for hints on how solve or further debug this problem. Christoph
