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 1CC02C6FA83 for ; Tue, 6 Sep 2022 14:14:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241482AbiIFOOo (ORCPT ); Tue, 6 Sep 2022 10:14:44 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56498 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241330AbiIFOMZ (ORCPT ); Tue, 6 Sep 2022 10:12:25 -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 57889883DA; Tue, 6 Sep 2022 06:47:47 -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 39E1F61568; Tue, 6 Sep 2022 13:46:40 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 45863C433D6; Tue, 6 Sep 2022 13:46:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1662471999; bh=VTPMBvWdW6xX6uPhDsZIFNhuBDFfP93MkaKCogd0LCc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=CDyb31iPHVfL1q9vfoUSBN2HOPVYlshsuLbMqUBSgUDuwTn9LWCuYByEiBNXRGK07 ICiZoE3j46ZcUY/8uBQg0KT6rJVKNoZFD2vjGC3RrIAAPhqL81XyHesQTvVNa9t9qg y1OiQZVnzdomeZQueL0GlKMI0ISLUoCtne9Mb9Cg= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jonathan Woithe , Johan Hovold Subject: [PATCH 5.19 113/155] USB: serial: ch341: fix lost character on LCR updates Date: Tue, 6 Sep 2022 15:31:01 +0200 Message-Id: <20220906132834.237102174@linuxfoundation.org> X-Mailer: git-send-email 2.37.3 In-Reply-To: <20220906132829.417117002@linuxfoundation.org> References: <20220906132829.417117002@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Johan Hovold 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 Signed-off-by: Greg Kroah-Hartman --- drivers/usb/serial/ch341.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) --- 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 * (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_de 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)