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=-1.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS autolearn=ham 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 5D2EDC43381 for ; Tue, 19 Mar 2019 15:00:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2EC1F2146E for ; Tue, 19 Mar 2019 15:00:01 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=mork.no header.i=@mork.no header.b="dL8Ar8Mh" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727800AbfCSO77 (ORCPT ); Tue, 19 Mar 2019 10:59:59 -0400 Received: from canardo.mork.no ([148.122.252.1]:33931 "EHLO canardo.mork.no" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726579AbfCSO77 (ORCPT ); Tue, 19 Mar 2019 10:59:59 -0400 Received: from miraculix.mork.no ([IPv6:2a02:2121:288:b97:1c73:e9ff:fe7f:e01b]) (authenticated bits=0) by canardo.mork.no (8.15.2/8.15.2) with ESMTPSA id x2JExgZg030715 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO); Tue, 19 Mar 2019 15:59:42 +0100 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=mork.no; s=b; t=1553007583; bh=NLo3Eqvh+LuCiP8bfsSoNSwQV9/09fbjfZEBj1mKbSo=; h=From:To:Cc:Subject:References:Date:Message-ID:From; b=dL8Ar8Mh1IC66ZsTvSDqmk3dcVZ0JGgm5yMAxzEJrR5voTUU4YuPs+mj3IRy2ycP/ S+0F2MCRgW6sJOLhVtPH7jv1rDanl2NSm6NRzbs5NE48NAJ6/qx4OMsHiZXvC/0hdq 3pfp98AMCNdBXnSJxnffH/UYga7joHbcNveUhUqg= Received: from bjorn by miraculix.mork.no with local (Exim 4.89) (envelope-from ) id 1h6GDI-00022w-O3; Tue, 19 Mar 2019 15:59:36 +0100 From: =?utf-8?Q?Bj=C3=B8rn_Mork?= To: =?utf-8?Q?M=C3=A5ns_Rullg=C3=A5rd?= Cc: Dan Williams , Johan Hovold , Greg Kroah-Hartman , linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] USB: serial: option: set driver_info for SIM5218 and compatibles Organization: m References: <20190226170710.12709-1-mans@mansr.com> <20190227083342.GJ4747@localhost> <20190227131315.GO4747@localhost> <20190319102840.GI6124@localhost> <20190319110819.GB3178@localhost> <20190319122719.GC3178@localhost> <20190319124358.GK6124@localhost> <6c89938b00ad289e1802f675bd00e288b1458d73.camel@redhat.com> Date: Tue, 19 Mar 2019 15:59:36 +0100 In-Reply-To: (=?utf-8?Q?=22M=C3=A5ns_Rullg?= =?utf-8?Q?=C3=A5rd=22's?= message of "Tue, 19 Mar 2019 14:35:18 +0000") Message-ID: <878sxa9ag7.fsf@miraculix.mork.no> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-Virus-Scanned: clamav-milter 0.100.2 at canardo X-Virus-Status: Clean Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org M=C3=A5ns Rullg=C3=A5rd writes: > Dan Williams writes: > >> TLDR; some firmware uses the DTR signal as an indicator to come out of >> low-power mode. Without doing so you cannot talk to the modem over any >> of it's ports, QMI, net, or serial. > > I must be missing something, but how does a network interface have a DTR > signal? It does not. But the network function is (ab)using the Comm class USB control message "SetControlLineState" to signal "wake up" from the host to the device. Which is perfectly fine since the USB function in question is vendor specific. The vendor can define any USB control message to mean anything they want. Reusing a Comm class message probably made sense to the firmware engineer designing this. We can only note and adapt. It doesn't have anything to do with DTR. Bj=C3=B8rn