594a53607e
In this way, we can check speed directly, don't need call usb_device_attach(), which has other conditions, such as checking the chardev is open. Signed-off-by: Gonglei <arei.gonglei@huawei.com> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>