Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752176AbXLZDmS (ORCPT ); Tue, 25 Dec 2007 22:42:18 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751477AbXLZDmE (ORCPT ); Tue, 25 Dec 2007 22:42:04 -0500 Received: from netrider.rowland.org ([192.131.102.5]:1738 "HELO netrider.rowland.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1751439AbXLZDmB (ORCPT ); Tue, 25 Dec 2007 22:42:01 -0500 Date: Tue, 25 Dec 2007 22:42:01 -0500 (EST) From: Alan Stern X-X-Sender: stern@netrider.rowland.org To: Andrew Morton cc: Victor Hahn , Kernel development list , Jaroslav Kysela , Takashi Iwai , USB list Subject: Re: Can't disconnect a USB sound device and connect another In-Reply-To: <20071225140450.b6d742bb.akpm@linux-foundation.org> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2744 Lines: 63 On Tue, 25 Dec 2007, Andrew Morton wrote: > On Sun, 23 Dec 2007 23:36:11 +0100 Victor Hahn wrote: > > > -----BEGIN PGP SIGNED MESSAGE----- > > Hash: SHA1 > > > > ... because it causes lsusb to freeze and gives me this in /var/log/messages: > > Has this always happened, or is it something we introduced in a recent > kernel? > > > Dec 23 23:27:04 cabrio kernel: usb 2-2: USB disconnect, address 5 > > Dec 23 23:27:04 cabrio kernel: PGD 110f2067 PUD 110f3067 PMD 0 > > Dec 23 23:27:04 cabrio kernel: CPU 0 > > Dec 23 23:27:04 cabrio kernel: Modules linked in: videodev v4l2_common > > v4l1_compat snd_rtctimer binfmt_misc rfcomm l2cap bluetooth capability ... > > Dec 23 23:27:04 cabrio kernel: Pid: 2052, comm: khubd Not tainted 2.6.23.11 #1 > > Dec 23 23:27:04 cabrio kernel: RIP: 0010:[_end+130488219/2130651808] > > [_end+130488219/2130651808] :snd:snd_ctl_dev_disconnect+0x6b/0xb0 > > Dec 23 23:27:04 cabrio kernel: RSP: 0018:ffff810037bfdc40 EFLAGS: 00010282 > > Dec 23 23:27:04 cabrio kernel: RAX: 0000000000000000 RBX: 0000000000100100 > > RCX: 0000000000000018 > > Dec 23 23:27:04 cabrio kernel: RDX: 0000000000020004 RSI: 000000000000001d > > RDI: ffff810013e98c08 > > Dec 23 23:27:04 cabrio kernel: RBP: ffff8100394631a8 R08: ffff810037bfc000 > > R09: 0000000000000000 ... > > Dec 23 23:27:04 cabrio kernel: Process khubd (pid: 2052, threadinfo > > ffff810037bfc000, task ffff81003d67d0c0) > > Dec 23 23:27:04 cabrio kernel: Stack: 0000000000000000 ffff810038850d00 > > ffff810039463000 ffff810039463150 > > Dec 23 23:27:04 cabrio kernel: 0000000000000000 ffffffff88281e69 > > ffff810038850d00 ffffffff882821ac > > Dec 23 23:27:04 cabrio kernel: 0000000000000000 0000000000000000 > > ffff810039463000 ffff8100394631e0 > > Dec 23 23:27:04 cabrio kernel: Call Trace: > > Dec 23 23:27:04 cabrio kernel: > > [_end+130500873/2130651808] :snd:snd_device_disconnect+0x59/0x90 > > Dec 23 23:27:04 cabrio kernel: ... > > Is there a way to exchange USB audio devices without rebooting? > > First we have to work out if it's a USB bug or an ALSA bug. I'd guess > ALSA, but not with a lot of confidence. > > Anyone? There have been similar reports of this bug. To me it looks like an ALSA problem. The routine in question, snd_ctl_dev_disconnect(), is an ALSA callback and doesn't contain any USB code. A good way to start would be to obtain a disassembly listing of that routine, so we can find out what C statement caused the bug. Alan Stern -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/