Re: [Qemu-devel] [PATCH] Re-attach usb device to kernel while usb_host_open fails

[Gonglei <arei.gonglei@huawei.com>]

On 2015/6/23 12:24, Lin Ma wrote:
> Signed-off-by: Lin Ma <lma@suse.com>
> ---
>  hw/usb/host-libusb.c | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/hw/usb/host-libusb.c b/hw/usb/host-libusb.c
> index 10f4735..7258c4d 100644
> --- a/hw/usb/host-libusb.c
> +++ b/hw/usb/host-libusb.c
> @@ -888,6 +888,11 @@ static int usb_host_open(USBHostDevice *s, libusb_device *dev)
>  fail:
>      trace_usb_host_open_failure(bus_num, addr);
>      if (s->dh != NULL) {
> +        qemu_remove_exit_notifier(&s->exit);
> +        QTAILQ_REMOVE(&hostdevs, s, next);

This change will cause a regression. For example, if an usb device's
(assume that it's usb1.0 device) speed does not match the ehci adapter,
then then invoking usb_host_open failed. if somebody changes the usb
device to an usb 2.0 device, it will not auto check because the device has
removed from the global hostdevs list.

So I think we don't need  do the above operations.

Regards,
-Gonglei

> +        usb_host_release_interfaces(s);
> +        libusb_reset_device(s->dh);
> +        usb_host_attach_kernel(s);
>          libusb_close(s->dh);
>          s->dh = NULL;
>          s->dev = NULL;
>