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=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 26F29C4CECE for ; Wed, 18 Sep 2019 06:24:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id ECAFD21925 for ; Wed, 18 Sep 2019 06:24:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1568787896; bh=EZNyax7R31/fUpxWagzOXKRSCF27HvnrImbZpRsL8sY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=WK2JL24two+BimXscAj6bucEHnCP6FwM8/hyTsiKO3K/WVPhfohKqo/mMGiyGMc7f HsWJGMwbbI/K6ZhfNzYisYR2xVfjfguPgYoISwV7z81AM5kBp9IUrSictjaWtAG2my e+qbiASC0MIl6n1m3t9q+UBwINM3HpOQurHtVk1w= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729939AbfIRGYy (ORCPT ); Wed, 18 Sep 2019 02:24:54 -0400 Received: from mail.kernel.org ([198.145.29.99]:45358 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729914AbfIRGYq (ORCPT ); Wed, 18 Sep 2019 02:24:46 -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 BE809218AF; Wed, 18 Sep 2019 06:24:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1568787885; bh=EZNyax7R31/fUpxWagzOXKRSCF27HvnrImbZpRsL8sY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=0od94pKX+gYwSXchVGSqT/7QT6rSEzJw7awGnx5vxMmDmdNZvDRwoNWlMAyovB7or IAxqAYZBBDcnxlD4tGxzuH+WEkpQk3DY2T/7cPxObVBWSJ2UQ/R3njfbNZnsZ3IMBs 4eiu54gV5ECtKp1RxHCnz6pjZg37IxbfAMFUDQiA= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Lars Melin , =?UTF-8?q?Bj=C3=B8rn=20Mork?= , "David S. Miller" Subject: [PATCH 5.2 02/85] cdc_ether: fix rndis support for Mediatek based smartphones Date: Wed, 18 Sep 2019 08:18:20 +0200 Message-Id: <20190918061234.200486731@linuxfoundation.org> X-Mailer: git-send-email 2.23.0 In-Reply-To: <20190918061234.107708857@linuxfoundation.org> References: <20190918061234.107708857@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: "Bjørn Mork" [ Upstream commit 4d7ffcf3bf1be98d876c570cab8fc31d9fa92725 ] A Mediatek based smartphone owner reports problems with USB tethering in Linux. The verbose USB listing shows a rndis_host interface pair (e0/01/03 + 10/00/00), but the driver fails to bind with [ 355.960428] usb 1-4: bad CDC descriptors The problem is a failsafe test intended to filter out ACM serial functions using the same 02/02/ff class/subclass/protocol as RNDIS. The serial functions are recognized by their non-zero bmCapabilities. No RNDIS function with non-zero bmCapabilities were known at the time this failsafe was added. But it turns out that some Wireless class RNDIS functions are using the bmCapabilities field. These functions are uniquely identified as RNDIS by their class/subclass/protocol, so the failing test can safely be disabled. The same applies to the two types of Misc class RNDIS functions. Applying the failsafe to Communication class functions only retains the original functionality, and fixes the problem for the Mediatek based smartphone. Tow examples of CDC functional descriptors with non-zero bmCapabilities from Wireless class RNDIS functions are: 0e8d:000a Mediatek Crosscall Spider X5 3G Phone CDC Header: bcdCDC 1.10 CDC ACM: bmCapabilities 0x0f connection notifications sends break line coding and serial state get/set/clear comm features CDC Union: bMasterInterface 0 bSlaveInterface 1 CDC Call Management: bmCapabilities 0x03 call management use DataInterface bDataInterface 1 and 19d2:1023 ZTE K4201-z CDC Header: bcdCDC 1.10 CDC ACM: bmCapabilities 0x02 line coding and serial state CDC Call Management: bmCapabilities 0x03 call management use DataInterface bDataInterface 1 CDC Union: bMasterInterface 0 bSlaveInterface 1 The Mediatek example is believed to apply to most smartphones with Mediatek firmware. The ZTE example is most likely also part of a larger family of devices/firmwares. Suggested-by: Lars Melin Signed-off-by: Bjørn Mork Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- drivers/net/usb/cdc_ether.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) --- a/drivers/net/usb/cdc_ether.c +++ b/drivers/net/usb/cdc_ether.c @@ -206,7 +206,15 @@ int usbnet_generic_cdc_bind(struct usbne goto bad_desc; } skip: - if (rndis && header.usb_cdc_acm_descriptor && + /* Communcation class functions with bmCapabilities are not + * RNDIS. But some Wireless class RNDIS functions use + * bmCapabilities for their own purpose. The failsafe is + * therefore applied only to Communication class RNDIS + * functions. The rndis test is redundant, but a cheap + * optimization. + */ + if (rndis && is_rndis(&intf->cur_altsetting->desc) && + header.usb_cdc_acm_descriptor && header.usb_cdc_acm_descriptor->bmCapabilities) { dev_dbg(&intf->dev, "ACM capabilities %02x, not really RNDIS?\n",