Re: [Qemu-devel] About usb passthru and speed mismatch

[Gerd Hoffmann]

On Do, 2015-06-11 at 23:47 +0800, Lin Ma wrote:
> Hi Gerd,
> 
> Based on the current implementation of 'usb_host_open' in 
> hw/usb/host-libusb.c,
> 
> When user performs usb_add, The usb device will be detached from kernel 
> first, Then be checked for speed mismatch second.
> If it found speed mismatch, The usb device isn't attached to guest, But 
> the usb device can't be reattached to kernel either.
> 
> I'd like to write patch to add 'usb_check_attach' before detaching the 
> device from kernel  _or_  add 'usb_host_attach_kernel' under 'fail:' of 
> usb_host_open, (the latter doesn't make sense I think).

Re-attach to the kernel when open fails (for whatever reasons) makes
perfect sense to me.

cheers,
  Gerd