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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7C3FFECAAD5 for ; Tue, 6 Sep 2022 12:25:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240120AbiIFMZI (ORCPT ); Tue, 6 Sep 2022 08:25:08 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46788 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240178AbiIFMYu (ORCPT ); Tue, 6 Sep 2022 08:24:50 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A5853501B4; Tue, 6 Sep 2022 05:21:41 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 81F86614F0; Tue, 6 Sep 2022 12:21:30 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id DD631C433C1; Tue, 6 Sep 2022 12:21:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1662466889; bh=PQWS0UART7yS+jRUH51JOWBPjnSkBvCuooSFXqUjy8M=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=K1EtzBcEUDpU92w9/S9s7gdjXxkdOUxTnKy6iEzlIN4tA339wI2fzQzS1YQ9YQelR 79WGO+u/Thh7YkFtsXNDiWcND8PJHVjZlEbldGgLJNHU39vWVT2wkfBDwI15ryJTeZ MyVRBgHJcu7lup5LKLXMv9cS5baFj5J/39OWIOlGSxcxYHHb6Q1PZ63mqrjPpjY+qt hafn1sa+PeTKB8LCtCUhjmzMop6aXmOGB7tNvYREelZTz54JWMG/uRwb72f+lr6x/P 3i0weEk4SfwgLu280RQ0fZ1wlN+67svFbzc3X3NzfYIPmR5p5cGBZ7S54k7Ms5lvSc a0QzbOC2T9OwA== Received: from johan by xi.lan with local (Exim 4.94.2) (envelope-from ) id 1oVXaA-00089U-Af; Tue, 06 Sep 2022 14:21:34 +0200 From: Johan Hovold To: Greg Kroah-Hartman Cc: stable@vger.kernel.org, linux-kernel@vger.kernel.org, Johan Hovold , Jonathan Woithe Subject: [PATCH stable-5.15 1/2] USB: serial: ch341: fix lost character on LCR updates Date: Tue, 6 Sep 2022 14:21:26 +0200 Message-Id: <20220906122127.31321-2-johan@kernel.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220906122127.31321-1-johan@kernel.org> References: <20220906122127.31321-1-johan@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org commit 8e83622ae7ca481c76c8fd9579877f6abae64ca2 upstream. Disable LCR updates for pre-0x30 devices which use a different (unknown) protocol for line control and where the current register write causes the next received character to be lost. Note that updating LCR using the INIT command has no effect on these devices either. Reported-by: Jonathan Woithe Tested-by: Jonathan Woithe Link: https://lore.kernel.org/r/Ys1iPTfiZRWj2gXs@marvin.atrad.com.au Fixes: 4e46c410e050 ("USB: serial: ch341: reinitialize chip on reconfiguration") Fixes: 55fa15b5987d ("USB: serial: ch341: fix baud rate and line-control handling") Cc: stable@vger.kernel.org # 4.10 Signed-off-by: Johan Hovold [ johan: adjust context to 5.15 ] Signed-off-by: Johan Hovold --- drivers/usb/serial/ch341.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) diff --git a/drivers/usb/serial/ch341.c b/drivers/usb/serial/ch341.c index b5a1864e9cfd..b787533aec64 100644 --- a/drivers/usb/serial/ch341.c +++ b/drivers/usb/serial/ch341.c @@ -97,7 +97,10 @@ struct ch341_private { u8 mcr; u8 msr; u8 lcr; + unsigned long quirks; + u8 version; + unsigned long break_end; }; @@ -271,6 +274,9 @@ static int ch341_set_baudrate_lcr(struct usb_device *dev, * (stop bits, parity and word length). Version 0x30 and above use * CH341_REG_LCR only and CH341_REG_LCR2 is always set to zero. */ + if (priv->version < 0x30) + return 0; + r = ch341_control_out(dev, CH341_REQ_WRITE_REG, CH341_REG_LCR2 << 8 | CH341_REG_LCR, lcr); if (r) @@ -323,7 +329,9 @@ static int ch341_configure(struct usb_device *dev, struct ch341_private *priv) r = ch341_control_in(dev, CH341_REQ_READ_VERSION, 0, 0, buffer, size); if (r < 0) goto out; - dev_dbg(&dev->dev, "Chip version: 0x%02x\n", buffer[0]); + + priv->version = buffer[0]; + dev_dbg(&dev->dev, "Chip version: 0x%02x\n", priv->version); r = ch341_control_out(dev, CH341_REQ_SERIAL_INIT, 0, 0); if (r < 0) -- 2.35.1