From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:33673) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Z4qoB-0000jD-1d for qemu-devel@nongnu.org; Tue, 16 Jun 2015 09:21:43 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Z4qo7-0003RT-OY for qemu-devel@nongnu.org; Tue, 16 Jun 2015 09:21:42 -0400 Received: from mx1.redhat.com ([209.132.183.28]:47293) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Z4qo7-0003Qv-K6 for qemu-devel@nongnu.org; Tue, 16 Jun 2015 09:21:39 -0400 Message-ID: <1434460896.15692.58.camel@redhat.com> From: Gerd Hoffmann Date: Tue, 16 Jun 2015 15:21:36 +0200 In-Reply-To: <5579AD97.1080906@suse.com> References: <5579AD97.1080906@suse.com> Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] About usb passthru and speed mismatch List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: lma@suse.com Cc: qemu-devel@nongnu.org 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