Re: [Qemu-devel] [BUG] qemu stuck when detach host-usb device

[Gerd Hoffmann]

On Tue, Nov 27, 2018 at 01:26:24AM +0000, linzhecheng wrote:
> Description of problem:
> The guest has a host-usb device(Kingston Technology DataTraveler 100 
> G3/G4/SE9 G2), which is attached
> to xhci controller(on host). Qemu will stuck if I detach it from guest.
> 
> How reproducible:
> 100%
> 
> Steps to Reproduce:
> 1.            Use usb stick to copy files in guest , make it busy working.
> 2.            virsh detach-device vm_name usb.xml
> 
> Then qemu will stuck for 20s, I found this is because 
> libusb_release_interface block for 20s.
> Dmesg prints:
> 
> [35442.034861] usb 4-2.1: Disable of device-initiated U1 failed.
> [35447.034993] usb 4-2.1: Disable of device-initiated U2 failed.
> [35452.035131] usb 4-2.1: Set SEL for device-initiated U1 failed.
> [35457.035259] usb 4-2.1: Set SEL for device-initiated U2 failed.
> 
> Is this a hardware error or software's bug?

I'd guess software error, could be is libusb or (host) linux kernel.
Cc'ing libusb-devel.

cheers,
  Gerd