From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:34616) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Z7ZFR-0002KO-0u for qemu-devel@nongnu.org; Tue, 23 Jun 2015 21:13:05 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Z7ZFL-0000Jl-RM for qemu-devel@nongnu.org; Tue, 23 Jun 2015 21:13:04 -0400 Received: from szxga02-in.huawei.com ([119.145.14.65]:25240) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Z7ZFL-0000Im-8Q for qemu-devel@nongnu.org; Tue, 23 Jun 2015 21:12:59 -0400 Message-ID: <558A03FF.8030003@huawei.com> Date: Wed, 24 Jun 2015 09:12:31 +0800 From: Gonglei MIME-Version: 1.0 References: <1435033463-13185-1-git-send-email-lma@suse.com> <55891904.9060508@huawei.com> <55897213.7000109@suse.com> In-Reply-To: <55897213.7000109@suse.com> Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit Subject: Re: [Qemu-devel] [PATCH] Re-attach usb device to kernel while usb_host_open fails List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: lma@suse.com, qemu-devel@nongnu.org, kraxel@redhat.com On 2015/6/23 22:49, Lin Ma wrote: > > 在 2015年06月23日 16:29, Gonglei 写道: >> On 2015/6/23 12:24, Lin Ma wrote: >>> Signed-off-by: Lin Ma >>> --- >>> 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. > In this situation, in my opinion, User should perform device_add to add the device again, Then the device will be added > to hostdevs list and can be auto checked again, right? > No, that's a regression if you ask users call device_add again. The purpose that we use bus/port to identify one usb device is can handle this scenario. After passing through one usb device by usb/port, the guest can auto check the device though you changed a usb device in the same physical port. > In addition, The usb_host_open will be performed 3 times until 's->errcount >= 3' while invoking usb_host_open failed. > If the usb device isn't removed from hostdevs list, It will be detached & re-attached 3 times. > Yes, that's no problem as a protecting logic. Regards, -Gonglei > > Thanks, > Lin >>> + 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; >>> >> >> >