Arch Linux

LeftyAce

Member

Registered: 2012-08-18

Posts: 162

Laptop doesn't react at all to a usb drive

Hi all,

I have arch running on a thinkpad X61. I have a 16GB Kingston USB thumb drive which the laptop refuses to recognize. I plug it into the USB port and nothing happens. It doesn't automount, and dmesg|tail shows nothing. lsblk doesn't show the device.

I am using a different (8GB) kingston USB thumb drive as my boot partition, and the machine boots off of it just fine. If I remove it and re plug it in, dmesg|tail shows a bunch of stuff about [sdb], and lsblk shows the device.

The thumb drive that doesn't work functions in other computers (windows machines). Although Windows complains that the filesystem is unclean (often happens to me after unmounting from my arch machine). The disk is formatted to fat32, if that matters.

Any ideas what's going on? Or how to diagnose?

Thanks in advance,

Lefty

EDIT:

After letting things sit for a few minutes, dmesg|tail does show some reaction. (The problem USB key was plugged in the whole time). The first "disconnect, device number 6" was when I removed the 8GB drive that works fine.

[  350.362527] usb 6-2: USB disconnect, device number 6
[  495.219408] perf interrupt took too long (2521 > 2495), lowering kernel.perf_event_max_sample_rate to 50100
[  555.623355] usb 6-2: new high-speed USB device number 8 using ehci-pci
[  555.753953] usb-storage 6-2:1.0: USB Mass Storage device detected
[  555.754200] scsi host10: usb-storage 6-2:1.0
[  555.837998] usb 6-2: USB disconnect, device number 8

Last edited by LeftyAce (2015-08-20 03:29:23)

mich41

Member

Registered: 2012-06-22

Posts: 796

Re: Laptop doesn't react at all to a usb drive

Maybe it's a hardware problem, e.g. the pendrive doesn't like your laptop's USB voltage or something like that. Try some powered hub.

LeftyAce

Member

Registered: 2012-08-18

Posts: 162

Re: Laptop doesn't react at all to a usb drive

Interesting. I tried plugging the pendrive into a usb port on my laptop dock, and it works. Does that indicate a problem with the drive or with the laptop? (Maybe some power saving setting in laptop-mode-tools?) Or is it not technically a problem but an incompatibility?

mich41

Member

Registered: 2012-06-22

Posts: 796

Re: Laptop doesn't react at all to a usb drive

It's hard to tell what's going on without a voltmeter. Maybe this pendrive is more picky about voltage than others (even though USB devices are supposed to work down to 4.5V) and you laptop provides less than the nominal 5V. Maybe your laptop enforces the 100mA current limit for unenumerated devices but the pendrive needs more (against USB spec). Maybe this limit is only enforced if you are on battery or is software controllable, maybe not.