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 0F593ECAAA1 for ; Tue, 6 Sep 2022 13:41:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232007AbiIFNl5 (ORCPT ); Tue, 6 Sep 2022 09:41:57 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38988 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233232AbiIFNkn (ORCPT ); Tue, 6 Sep 2022 09:40:43 -0400 Received: from sin.source.kernel.org (sin.source.kernel.org [IPv6:2604:1380:40e1:4800::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 67F7A7C51A; Tue, 6 Sep 2022 06:37:17 -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 sin.source.kernel.org (Postfix) with ESMTPS id 01A8BCE1780; Tue, 6 Sep 2022 13:35:53 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id BEED1C433C1; Tue, 6 Sep 2022 13:35:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1662471351; bh=2kANwVg4Rl6NnGBq0LzTxlY7t3U55WnFxJwykv2/8uQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=VH2sCZmfrhMbPNBS7GpCupuP0bHBDnYPGC7wOI4SjhoKlOtkjXwVXpnI17YvJ1i0L lvcMXjQsFQlz1gEPsQ81dy5RsyccmdxNUEO19NxDqwRYPmj/VzFmG4XWkIWEcTracf sKZ6g7H0lr2P4jly64wP26DnWtbyvoZnU7fSzp1g= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jonathan Woithe , Johan Hovold Subject: [PATCH 5.10 79/80] USB: serial: ch341: fix lost character on LCR updates Date: Tue, 6 Sep 2022 15:31:16 +0200 Message-Id: <20220906132820.408184247@linuxfoundation.org> X-Mailer: git-send-email 2.37.3 In-Reply-To: <20220906132816.936069583@linuxfoundation.org> References: <20220906132816.936069583@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: stable@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 [ johan: adjust context to 5.15 ] 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; }; @@ -271,6 +274,9 @@ 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) @@ -323,7 +329,9 @@ static int ch341_configure(struct usb_de 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)