From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_2 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id ED921C433DF for ; Mon, 8 Jun 2020 19:21:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C024A2068D for ; Mon, 8 Jun 2020 19:21:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726409AbgFHTVq (ORCPT ); Mon, 8 Jun 2020 15:21:46 -0400 Received: from mx2.suse.de ([195.135.220.15]:36502 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726227AbgFHTVq (ORCPT ); Mon, 8 Jun 2020 15:21:46 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id 9B44EAE35; Mon, 8 Jun 2020 19:21:48 +0000 (UTC) Message-ID: <1591644088.24937.7.camel@suse.com> Subject: Re: ttyACM: disabled by hub (EMI?), re-enabling... Causes garbage chars & disconnect From: Oliver Neukum To: Joakim Tjernlund , "linux-usb@vger.kernel.org" Date: Mon, 08 Jun 2020 21:21:28 +0200 In-Reply-To: <294b2e8330b8c04652ffbab7829dd2cbfa2cf081.camel@infinera.com> References: <6a4fe396ab5ae6cda548e904c57bc823103999d7.camel@infinera.com> <1590418977.2838.16.camel@suse.com> <1590482853.2838.26.camel@suse.com> <8cf71160e703a18b28d27a844406d42f6cadf39b.camel@infinera.com> <1590488084.2838.34.camel@suse.com> <42c92312c74e90e5507de4103bd15bbbe175f98d.camel@infinera.com> <4c2bd25aa7f6672cb132487f7af6a787ffc1fab6.camel@infinera.com> <1590568683.2838.42.camel@suse.com> <1590576068.2838.56.camel@suse.com> <9971e8a97ea0f9d63864829fd8f2f4db897fc131.camel@infinera.com> <1591607631.24937.3.camel@suse.com> <914176111c9eee651f402b499bc5ec49ff634e00.camel@infinera.com> <1591630857.24937.5.camel@suse.com> <294b2e8330b8c04652ffbab7829dd2cbfa2cf081.camel@infinera.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.26.6 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-usb-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org Am Montag, den 08.06.2020, 16:00 +0000 schrieb Joakim Tjernlund: > User space already does this, but the automatic ECHOing that happens at open > is not possible to address in user space. The buffered chars are sent to both > the terminal app(putty/minicom etc.) and over the wire to the shell waiting there > and that is the problem. There is no way to prevent that ECHO back over the wire(USB) > as the default is to ECHO and one have to open the tty to change to non ECHO. Hi, this is correct, but not specific to CDC-ACM. Could you ask the serial maintainers and look at what SUS respectively POSIX have to say about correct behavior? Regards Oliver