Re: USB device cannot be reconnected and khubd "blocked for more than120 seconds"

From: Alex Riesen
Date: Sat Jan 12 2013 - 02:49:14 EST


On Fri, Jan 11, 2013 at 10:04 PM, Alex Riesen <raa.lkml@xxxxxxxxx> wrote:
> Hi,
>
> the USB stick (an Cruzer Titanium 2GB) was not recognized at any of
> the USB ports of this system (an System76 lemu4 laptop, XHCI device)
> after it was removed. If I attempt to insert it again in any of the
> ports (one of the two USB3, or the USB2) the led on the stick lights
> up shortly and if off again. There is no media detection messages in
> the dmesg output, only that from the first time:
>
> usb 1-1.2: new high-speed USB device number 3 using ehci-pci
> usb 1-1.2: New USB device found, idVendor=0781, idProduct=5408
> usb 1-1.2: New USB device strings: Mfr=1, Product=2, SerialNumber=3
> usb 1-1.2: Product: U3 Titanium
> usb 1-1.2: Manufacturer: SanDisk Corporation
> usb 1-1.2: SerialNumber: 0000187A3A60F1E9
> scsi6 : usb-storage 1-1.2:1.0
> io scheduler deadline registered (default)
> usb 1-1.2: USB disconnect, device number 3
>
> The kernel is v3.8-rc3. I never had this problem in 3.7. I could almost
> reproduce the problem later in a simplified setup (init=/bin/bash) on
> USB3 ports by inserting and removing the stick quickly. Almost - because
> the USB3 ports recovered after some time, while the USB2 port never
> experienced the problem.

One more detail: I usually use the "noop" elevator. That time it was
the "deadline". And I just reproduced it easily with "deadline".
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