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=-10.5 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, 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 E69D9C43387 for ; Fri, 11 Jan 2019 14:21:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B088621783 for ; Fri, 11 Jan 2019 14:21:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1547216478; bh=+8bnEF3Qj6Vv9Ay0hcuuYFkwcWYH/2+Xe7fvK/GTWtg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=rTJ8DApEsenisBMBN3XdurqGoM3C6ZePSn31+9SZKDi7qqsjrPsYPGGjJnSc+uycL 77HFpPAr8AGU1u+juIJjN7nwT7zjdeFkuLASx0qRwYDZTmBGFFAsuADOOBetLIrlok jea0eFObmUUjx9e3k6dy/ac1Yl4QM5cX2SI4chhQ= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731691AbfAKOUD (ORCPT ); Fri, 11 Jan 2019 09:20:03 -0500 Received: from mail.kernel.org ([198.145.29.99]:37472 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731874AbfAKOUC (ORCPT ); Fri, 11 Jan 2019 09:20:02 -0500 Received: from localhost (5356596B.cm-6-7b.dynamic.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 9D6E62177B; Fri, 11 Jan 2019 14:20:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1547216401; bh=+8bnEF3Qj6Vv9Ay0hcuuYFkwcWYH/2+Xe7fvK/GTWtg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=X1DACgPxvKaHKBXTSGFAEphdJ1yF5rdbMNPK2m8W9g/2RUxkSCc7j7R+Pt9wRa7sE urGmN2OOlmeMSGuksO68jLEJ0YeTWmZvuiM+OGPw3eP0gBSPv10zLkMoqY78NWtwOh geeNDDE7kiX2FqYLY7bGtRNbpgv3KgB7nowCkIy4= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Macpaul Lin , Johan Hovold , Oliver Neukum Subject: [PATCH 4.4 49/88] cdc-acm: fix abnormal DATA RX issue for Mediatek Preloader. Date: Fri, 11 Jan 2019 15:08:18 +0100 Message-Id: <20190111131053.347555508@linuxfoundation.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190111131045.137499039@linuxfoundation.org> References: <20190111131045.137499039@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review X-Patchwork-Hint: ignore MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Macpaul Lin commit eafb27fa5283599ce6c5492ea18cf636a28222bb upstream. Mediatek Preloader is a proprietary embedded boot loader for loading Little Kernel and Linux into device DRAM. This boot loader also handle firmware update. Mediatek Preloader will be enumerated as a virtual COM port when the device is connected to Windows or Linux OS via CDC-ACM class driver. When the USB enumeration has been done, Mediatek Preloader will send out handshake command "READY" to PC actively instead of waiting command from the download tool. Since Linux 4.12, the commit "tty: reset termios state on device registration" (93857edd9829e144acb6c7e72d593f6e01aead66) causes Mediatek Preloader receiving some abnoraml command like "READYXX" as it sent. This will be recognized as an incorrect response. The behavior change also causes the download handshake fail. This change only affects subsequent connects if the reconnected device happens to get the same minor number. By disabling the ECHO termios flag could avoid this problem. However, it cannot be done by user space configuration when download tool open /dev/ttyACM0. This is because the device running Mediatek Preloader will send handshake command "READY" immediately once the CDC-ACM driver is ready. This patch wants to fix above problem by introducing "DISABLE_ECHO" property in driver_info. When Mediatek Preloader is connected, the CDC-ACM driver could disable ECHO flag in termios to avoid the problem. Signed-off-by: Macpaul Lin Cc: stable@vger.kernel.org Reviewed-by: Johan Hovold Acked-by: Oliver Neukum Signed-off-by: Greg Kroah-Hartman --- drivers/usb/class/cdc-acm.c | 10 ++++++++++ drivers/usb/class/cdc-acm.h | 1 + 2 files changed, 11 insertions(+) --- a/drivers/usb/class/cdc-acm.c +++ b/drivers/usb/class/cdc-acm.c @@ -507,6 +507,13 @@ static int acm_tty_install(struct tty_dr if (retval) goto error_init_termios; + /* + * Suppress initial echoing for some devices which might send data + * immediately after acm driver has been installed. + */ + if (acm->quirks & DISABLE_ECHO) + tty->termios.c_lflag &= ~ECHO; + tty->driver_data = acm; return 0; @@ -1677,6 +1684,9 @@ static const struct usb_device_id acm_id { USB_DEVICE(0x0e8d, 0x0003), /* FIREFLY, MediaTek Inc; andrey.arapov@gmail.com */ .driver_info = NO_UNION_NORMAL, /* has no union descriptor */ }, + { USB_DEVICE(0x0e8d, 0x2000), /* MediaTek Inc Preloader */ + .driver_info = DISABLE_ECHO, /* DISABLE ECHO in termios flag */ + }, { USB_DEVICE(0x0e8d, 0x3329), /* MediaTek Inc GPS */ .driver_info = NO_UNION_NORMAL, /* has no union descriptor */ }, --- a/drivers/usb/class/cdc-acm.h +++ b/drivers/usb/class/cdc-acm.h @@ -134,3 +134,4 @@ struct acm { #define QUIRK_CONTROL_LINE_STATE BIT(6) #define CLEAR_HALT_CONDITIONS BIT(7) #define SEND_ZERO_PACKET BIT(8) +#define DISABLE_ECHO BIT(9)