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 4EFC2ECAAA1 for ; Tue, 6 Sep 2022 11:23:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238831AbiIFLX5 (ORCPT ); Tue, 6 Sep 2022 07:23:57 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38886 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239795AbiIFLX4 (ORCPT ); Tue, 6 Sep 2022 07:23:56 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7156A75481 for ; Tue, 6 Sep 2022 04:23:55 -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 E9A99614C6 for ; Tue, 6 Sep 2022 11:23:54 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id F4178C433D7; Tue, 6 Sep 2022 11:23:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1662463434; bh=oCxS1wNTE6FbJ18KOjhTkxPIQnxVXChofSJmSsAQLME=; h=Subject:To:Cc:From:Date:From; b=UOCugHNJlqp1+sVy/jgCzPvRG/hNSbptq6DnDpbo68Yp07Uj9pWfvjG1+p1uShFCS b2ABkrt4/zyXWjd30MNDOx8OZ+ZQAbWgvOEiEKJ7dxHsW79Sp4O/VIj0c+psubkk5h 6aKzs5/U5GSjiKSvA9Vq6OVJ3XLqDN/hQlvWapAU= Subject: FAILED: patch "[PATCH] USB: serial: ch341: fix lost character on LCR updates" failed to apply to 4.19-stable tree To: johan@kernel.org, jwoithe@just42.net Cc: From: Date: Tue, 06 Sep 2022 13:23:42 +0200 Message-ID: <1662463422127119@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org The patch below does not apply to the 4.19-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 8e83622ae7ca481c76c8fd9579877f6abae64ca2 Mon Sep 17 00:00:00 2001 From: Johan Hovold Date: Wed, 31 Aug 2022 10:15:24 +0200 Subject: [PATCH] USB: serial: ch341: fix lost character on LCR updates 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 diff --git a/drivers/usb/serial/ch341.c b/drivers/usb/serial/ch341.c index 2798fca71261..2bcce172355b 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; }; @@ -265,6 +268,9 @@ 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) @@ -308,7 +314,9 @@ 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) return r; - 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)