From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753838Ab0ASOZe (ORCPT ); Tue, 19 Jan 2010 09:25:34 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753697Ab0ASOZd (ORCPT ); Tue, 19 Jan 2010 09:25:33 -0500 Received: from earthlight.etchedpixels.co.uk ([81.2.110.250]:44320 "EHLO www.etchedpixels.co.uk" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753277Ab0ASOZb (ORCPT ); Tue, 19 Jan 2010 09:25:31 -0500 Date: Tue, 19 Jan 2010 14:26:57 +0000 From: Alan Cox To: Oliver Neukum Cc: Matthew Garrett , dvomlehn@cisco.com, gregkh@suse.de, linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [REGRESSION] "USB: use kfifo to buffer usb-generic serial writes" causes gobi_loader to hang Message-ID: <20100119142657.02856d15@lxorguk.ukuu.org.uk> In-Reply-To: <201001191457.00504.oliver@neukum.org> References: <20100117025535.GB7045@srcf.ucam.org> <201001191420.29652.oliver@neukum.org> <20100119132934.0c1688f7@lxorguk.ukuu.org.uk> <201001191457.00504.oliver@neukum.org> X-Mailer: Claws Mail 3.7.3 (GTK+ 2.18.5; x86_64-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > The log shows no call to usb_serial_generic_write_room() > Do you consider this a bug in the tty layer? Actually this all makes sense because of where it was hanging. A reply of 0 to the tty->ops->write will cause it to either return (O_NONBLOCK) or sleep in the n_tty write code waiting for a write_wait wakeup (tty_wakeup(tty)) So the fix does indeed look correct.