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 81965ECAAD5 for ; Tue, 6 Sep 2022 14:17:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241450AbiIFORy (ORCPT ); Tue, 6 Sep 2022 10:17:54 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35372 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241578AbiIFOOy (ORCPT ); Tue, 6 Sep 2022 10:14:54 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E1B8E89CE2; Tue, 6 Sep 2022 06:49:16 -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 ams.source.kernel.org (Postfix) with ESMTPS id 3F310B818DC; Tue, 6 Sep 2022 13:49:16 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 037F1C433B5; Tue, 6 Sep 2022 13:49:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1662472155; bh=JASWaJC+v+2H2clv/pvy30CI6OB9y7udfCrEM/Tp+bg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=sXJu/gTM8M0csvbwkSHD5aV2D1GnM7ZpvkAb2usshGOUSxs5UVgumK9MijJomf/8p 0JJwu5izG/2S5vlSoJt8Ew79cEVLujUQgjsRAi4Uaq0tgG2R2hjfgv9VMRjG4rYv2b R2k+VzaaZVudhBMjjh6lgrNejPjroIuMYBPkH0KKQLU68j3XoN3fQXpsc5yPQOC/OC ywmi+rUDrwdKdSovkGe01aGQCAwpyHL2wlp9FjVU7dNOrP9VwtiAP5pT1BJ2ygJrfx /MF/VL5cbvnbXgzP/Aw/nNU3ArcANfruumiqM6NihdTuqnW1EoAbZPewK7HfnQkNOw Wyaia2A7bslSA== Received: from johan by xi.lan with local (Exim 4.94.2) (envelope-from ) id 1oVYx5-00050Y-Ld; Tue, 06 Sep 2022 15:49:19 +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-4.19 4/4] USB: serial: ch341: fix disabled rx timer on older devices Date: Tue, 6 Sep 2022 15:49:15 +0200 Message-Id: <20220906134915.19225-5-johan@kernel.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220906134915.19225-1-johan@kernel.org> References: <20220906134915.19225-1-johan@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org commit 41ca302a697b64a3dab4676e01d0d11bb184737d upstream. At least one older CH341 appears to have the RX timer enable bit inverted so that setting it disables the RX timer and prevents the FIFO from emptying until it is full. Only set the RX timer enable bit for devices with version newer than 0x27 (even though this probably affects all pre-0x30 devices). 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") Cc: stable@vger.kernel.org # 4.10 Signed-off-by: Johan Hovold [ johan: backport to 5.4 ] Signed-off-by: Johan Hovold --- drivers/usb/serial/ch341.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/drivers/usb/serial/ch341.c b/drivers/usb/serial/ch341.c index 58b5fd95b29f..7eabb1bfafde 100644 --- a/drivers/usb/serial/ch341.c +++ b/drivers/usb/serial/ch341.c @@ -176,8 +176,12 @@ static int ch341_set_baudrate_lcr(struct usb_device *dev, /* * CH341A buffers data until a full endpoint-size packet (32 bytes) * has been received unless bit 7 is set. + * + * At least one device with version 0x27 appears to have this bit + * inverted. */ - a |= BIT(7); + if (priv->version > 0x27) + a |= BIT(7); r = ch341_control_out(dev, CH341_REQ_WRITE_REG, 0x1312, a); if (r) -- 2.35.1