Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752665AbbGNAH6 (ORCPT ); Mon, 13 Jul 2015 20:07:58 -0400 Received: from out1-smtp.messagingengine.com ([66.111.4.25]:53207 "EHLO out1-smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751911AbbGNAH5 (ORCPT ); Mon, 13 Jul 2015 20:07:57 -0400 X-Greylist: delayed 569 seconds by postgrey-1.27 at vger.kernel.org; Mon, 13 Jul 2015 20:07:57 EDT X-Sasl-enc: OjJnN/g6VQfYEH1Ap3wzgDAcuEb965uVjZjgkeo4KfHH 1436831905 Message-ID: <55A450A0.4080806@imap.cc> Date: Tue, 14 Jul 2015 01:58:24 +0200 From: Tilman Schmidt User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.7.0 MIME-Version: 1.0 To: Peter Hurley , Paul Bolle CC: netdev@vger.kernel.org, David Miller , Hansjoerg Lipp , linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/2] isdn/gigaset: reset tty->receive_room when attaching ser_gigaset References: <55A44662.4080706@hurleysoftware.com> In-Reply-To: <55A44662.4080706@hurleysoftware.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1507 Lines: 34 Am 14.07.2015 um 01:14 schrieb Peter Hurley: > On 07/13/2015 06:37 PM, Tilman Schmidt wrote: >> Commit 79901317ce80 ("n_tty: Don't flush buffer when closing ldisc"), >> first merged in kernel release 3.10, caused the following regression >> in the Gigaset M101 driver: >> >> Before that commit, when closing the N_TTY line discipline in >> preparation to switching to N_GIGASET_M101, receive_room would be >> reset to a non-zero value by the call to n_tty_flush_buffer() in >> n_tty's close method. With the removal of that call, receive_room >> might be left at zero, blocking data reception on the serial line. > > That commit didn't cause the problem; it was a bug all along. Sure. That's why it is correctly fixed in the Gigaset driver. But before that commit the bug was never actually triggered. So that commit defines the point in the commit history from which the fix is needed, and therefore needs to be mentioned in order to decide which stable releases will need the fix. > Non-flow controlling line disciplines _must_ set tty->receive_room > on line discipline open because they are declaring that every > input they can accept that much data. I have submitted a corresponding fix to the line discipline documentation separately. Thanks, Tilman -- 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/