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=-0.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS 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 04C6FC433DF for ; Tue, 19 May 2020 12:54:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D7C1520823 for ; Tue, 19 May 2020 12:54:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1589892843; bh=v0xajYSa5l3lB+zy1YykxNt0Lf99pTWzRwzHhEAnwq8=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=b6nPkUqABvQs2iIVEHCDAYnxyhIHObUCCatH3gCaPGnIMNtYOyw1UyjAKTGO7r1fY WFedVXUtP5ZPsOE1sW0/xClYV5mZ3evX5u624jOoSPqi17Es9Qco49G8JU/aRfpNT3 izYXsekxJvF+g0Od1kA2jGo16JCXVxXbVaLTj4a4= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726880AbgESMyD (ORCPT ); Tue, 19 May 2020 08:54:03 -0400 Received: from mail.kernel.org ([198.145.29.99]:47670 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726169AbgESMyD (ORCPT ); Tue, 19 May 2020 08:54:03 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 7356E2081A; Tue, 19 May 2020 12:54:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1589892842; bh=v0xajYSa5l3lB+zy1YykxNt0Lf99pTWzRwzHhEAnwq8=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=oEmyiLtT4w5ukqDhd79M1G6HbLqfi+CD7H3Vx6b5ObjSdLq03Cw1DN2r2RSQEMoDM cdM8avLMcihCCG4kvwCjJP5XPYxbqR+jeGV2r72QkHqcyeOdKJ1glQ6cQIAKfXLTPG +guhOAHZ5VkyQNCOqZTjDO7d/uPZvBu1k7KBDimo= Date: Tue, 19 May 2020 14:54:00 +0200 From: Greg KH To: Joakim Tjernlund Cc: "linux-usb@vger.kernel.org" Subject: Re: ttyACM strange chars appearing at connect Message-ID: <20200519125400.GA410029@kroah.com> References: <52b8c126634058e3a455dc0ab8b0c542916db543.camel@infinera.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <52b8c126634058e3a455dc0ab8b0c542916db543.camel@infinera.com> Sender: linux-usb-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org On Tue, May 19, 2020 at 12:14:55PM +0000, Joakim Tjernlund wrote: > Whenever we connect a Linux laptop(4.19.118) to our ttyACM serial gadget we can see som strange > chars appearing in our gadget: > 03�`3�03�x�x(in hex: 3033 efbf bd60 33ef bfbd 3033 efbf bd78 efbf bd78) > They appear witch c.a 1 sec in between. > I assume it is the laptops ACM driver emitting those, but why? Can these chars be turned off? It's a program on your laptop probing the device. Usually modemmanager or something like that. greg k-h