From patchwork Wed Aug 31 08:15:25 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Johan Hovold X-Patchwork-Id: 601765 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 7B43AECAAD3 for ; Wed, 31 Aug 2022 08:15:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231357AbiHaIPr (ORCPT ); Wed, 31 Aug 2022 04:15:47 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59908 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231262AbiHaIPk (ORCPT ); Wed, 31 Aug 2022 04:15:40 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5CF544F69B; Wed, 31 Aug 2022 01:15:38 -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 1A79DB81FA0; Wed, 31 Aug 2022 08:15:37 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id D6F5BC433D6; Wed, 31 Aug 2022 08:15:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1661933735; bh=eSm/Gxj0y/7tZ+reMqFOc9ngJfIpQ318HJ976ReDtSk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ijr5kKeYGJiF+80G6s1jxzwVPFiyqgMFN8x7i3ch1TO+jsOprvCgF8ulnU8vD/Tk8 qMNtBMKEH0YVssbuTGHdsEZoGyS5hGhBwEbQug2w5RiNtoL+xqaQ8EzssWKYKIgvtg UoqLxDgfHkpM+0BfeHjvvCueLiljKOeAY0dDd36zr9w2kyKQd+91tOIV8CwApWpXxb +Kck1xNqcYqHVwbTcX25WapHwO0dK0dhEFNwfFpIqaMs/0zK/lvI55fsSV3eTIc+2l 9YgkrbyVoebSQUN51a9qhIS0vR44lu6BWmSiwEmYuM6pk4fuxVNH+SxjTV7HrXUTcw mCgH+oMOZGpDg== Received: from johan by xi.lan with local (Exim 4.94.2) (envelope-from ) id 1oTIsn-0007xC-QF; Wed, 31 Aug 2022 10:15:33 +0200 From: Johan Hovold To: Johan Hovold , Jonathan Woithe Cc: linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: [PATCH 2/2] USB: serial: ch341: fix disabled rx timer on older devices Date: Wed, 31 Aug 2022 10:15:25 +0200 Message-Id: <20220831081525.30557-3-johan@kernel.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220831081525.30557-1-johan@kernel.org> References: <20220831081525.30557-1-johan@kernel.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org 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 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 --- 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 2bcce172355b..af01a462cc43 100644 --- a/drivers/usb/serial/ch341.c +++ b/drivers/usb/serial/ch341.c @@ -253,8 +253,12 @@ 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. */ - val |= BIT(7); + if (priv->version > 0x27) + val |= BIT(7); r = ch341_control_out(dev, CH341_REQ_WRITE_REG, CH341_REG_DIVISOR << 8 | CH341_REG_PRESCALER,