Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755252AbaDNOFB (ORCPT ); Mon, 14 Apr 2014 10:05:01 -0400 Received: from lxorguk.ukuu.org.uk ([81.2.110.251]:42991 "EHLO lxorguk.ukuu.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754473AbaDNOFA (ORCPT ); Mon, 14 Apr 2014 10:05:00 -0400 Date: Mon, 14 Apr 2014 15:04:38 +0100 From: One Thousand Gnomes To: Oliver Neukum Cc: Johan Hovold , Jiri Slaby , Greg Kroah-Hartman , linux-kernel@vger.kernel.org, linux-usb@vger.kernel.org, Peter Hurley , Xiao Jin , david.a.cohen@linux.intel.com, yanmin.zhang@intel.com Subject: Re: [RFC 1/2] n_tty: fix dropped output characters Message-ID: <20140414150438.2737893d@alan.etchedpixels.co.uk> In-Reply-To: <1397480749.16591.24.camel@linux-fkkt.site> References: <20140411093715.GA17522@localhost> <1397209285-15471-1-git-send-email-jhovold@gmail.com> <20140414135333.1057aac8@alan.etchedpixels.co.uk> <1397480749.16591.24.camel@linux-fkkt.site> Organization: Intel Corporation X-Mailer: Claws Mail 3.8.1 (GTK+ 2.24.20; x86_64-pc-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 On Mon, 14 Apr 2014 15:05:49 +0200 Oliver Neukum wrote: > On Mon, 2014-04-14 at 13:53 +0100, One Thousand Gnomes wrote: > > On Fri, 11 Apr 2014 11:41:24 +0200 > > Johan Hovold wrote: > > > > > Fix characters being dropped by n_tty_write() due to a failure to > > > check the return value of tty_put_char() in do_output_char(). > > > > > > Characters are currently being dropped by write if a tty driver claims > > > to have write room available, but still fails to buffer any data > > > > Your driver is buggy. If you advertise a buffer you must honour it and > > neither shrink nor revoke it. > > Is that a general rule or does it apply only till the next write? Its a general rule. If you've advertised 5 bytes then you can only advertise 0 after 5 bytes have been sent your way (or a hangup etc occurred). Alan -- 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/