From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757803Ab0BCW6N (ORCPT ); Wed, 3 Feb 2010 17:58:13 -0500 Received: from smtp-out003.kontent.com ([81.88.40.217]:52059 "EHLO smtp-out003.kontent.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757587Ab0BCW6M (ORCPT ); Wed, 3 Feb 2010 17:58:12 -0500 From: Oliver Neukum To: Matthew Garrett Subject: Re: [REGRESSION] "USB: use kfifo to buffer usb-generic serial writes" causes gobi_loader to hang Date: Wed, 3 Feb 2010 23:58:03 +0100 User-Agent: KMail/1.12.2 (Linux/2.6.33-rc6-0.1-default; KDE/4.3.1; x86_64; ; ) Cc: dvomlehn@cisco.com, gregkh@suse.de, linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org References: <20100117025535.GB7045@srcf.ucam.org> <201002031821.39532.oliver@neukum.org> <20100203223737.GA2578@srcf.ucam.org> In-Reply-To: <20100203223737.GA2578@srcf.ucam.org> MIME-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Message-Id: <201002032358.03552.oliver@neukum.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Am Mittwoch, 3. Februar 2010 23:37:37 schrieb Matthew Garrett: > On Wed, Feb 03, 2010 at 06:21:39PM +0100, Oliver Neukum wrote: > > Am Mittwoch, 3. Februar 2010 17:46:59 schrieb Matthew Garrett: > > > > If the FIFO is full we can do nothing. Please try the attached patch. > > > > > > Doesn't help, I'm afraid. Does anyone have any idea why the change to > > > use kfifo would cause this? > > > > The logic seems sound. That is unless the kfifo code is acting up. > > Could you printk the value kfifo_len returns in usb_serial_generic_write_start()? > > kfifo_len is 4096 when it gets into the fifo_full situation. Then this won't explain it either. Do you get to the line: dbg("%s - starting IO", __func__); before it hangs? Regards Oliver