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 X-Spam-Level: X-Spam-Status: No, score=-11.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4DF88C433E4 for ; Fri, 29 May 2020 07:41:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2BEEE2074D for ; Fri, 29 May 2020 07:41:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1590738102; bh=dO7H8/ASzN8PqPoGgz9MHXYUzd4Bu+PpMHZaPiQDv2Q=; h=Subject:To:From:Date:List-ID:From; b=RuwLLu/JWL+SlXdLQMtjBHrCqa9s9odPnhyb+KDg8EPkbMxDGSb6guWpYtEmAat50 qyvS8K5saudvS+HRpORsLKef4f2+04UuxyYX2BYpNy0c83U9GpDJUUJj2W8aw16Iqh rktLuSeiAO+aPRuZG2QNXj0kDMh+qkuxsy1Gfm6s= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726978AbgE2Hll (ORCPT ); Fri, 29 May 2020 03:41:41 -0400 Received: from mail.kernel.org ([198.145.29.99]:52544 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726742AbgE2Hlk (ORCPT ); Fri, 29 May 2020 03:41:40 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id B3B8B20810; Fri, 29 May 2020 07:41:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1590738100; bh=dO7H8/ASzN8PqPoGgz9MHXYUzd4Bu+PpMHZaPiQDv2Q=; h=Subject:To:From:Date:From; b=niziWEtY86GP3q/NnfgKKMp9ZJb933KQxuhcXWWFEsg01DmIBfrYT5oMhdPQJF+Vr PAzZcPpWggdzBT9lcvbjMENWMbHTH+pRJ48HswBESsHNLf5yKQaHmSg+4G5ZaEiuzz Rq2yUJnFc5ss3Y4Tft+11G4o4gvCn1h4ul5m63VA= Subject: patch "USB: serial: ch341: fix lockup of devices with limited prescaler" added to usb-testing To: johan@kernel.org, public@hansmi.ch, stable@vger.kernel.org From: Date: Fri, 29 May 2020 09:41:28 +0200 Message-ID: <1590738088179163@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org This is a note to let you know that I've just added the patch titled USB: serial: ch341: fix lockup of devices with limited prescaler to my usb git tree which can be found at git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git in the usb-testing branch. The patch will show up in the next release of the linux-next tree (usually sometime within the next 24 hours during the week.) The patch will be merged to the usb-next branch sometime soon, after it passes testing, and the merge window is open. If you have any questions about this process, please let me know. >From c432df155919582a3cefa35a8f86256c830fa9a4 Mon Sep 17 00:00:00 2001 From: Johan Hovold Date: Thu, 14 May 2020 11:36:45 +0200 Subject: USB: serial: ch341: fix lockup of devices with limited prescaler Michael Hanselmann reports that [a] subset of all CH341 devices stop responding to bulk transfers, usually after the third byte, when the highest prescaler bit (0b100) is set. There is one exception, namely a prescaler of exactly 0b111 (fact=1, ps=3). Fix this by forcing a lower base clock (fact = 0) whenever needed. This specifically makes the standard rates 110, 134 and 200 bps work again with these devices. Fixes: 35714565089e ("USB: serial: ch341: reimplement line-speed handling") Cc: stable # 5.5 Reported-by: Michael Hanselmann Link: https://lore.kernel.org/r/20200514141743.GE25962@localhost Signed-off-by: Johan Hovold --- drivers/usb/serial/ch341.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-) diff --git a/drivers/usb/serial/ch341.c b/drivers/usb/serial/ch341.c index f2b93f4554a7..89675ee29645 100644 --- a/drivers/usb/serial/ch341.c +++ b/drivers/usb/serial/ch341.c @@ -73,6 +73,8 @@ #define CH341_LCR_CS6 0x01 #define CH341_LCR_CS5 0x00 +#define CH341_QUIRK_LIMITED_PRESCALER BIT(0) + static const struct usb_device_id id_table[] = { { USB_DEVICE(0x4348, 0x5523) }, { USB_DEVICE(0x1a86, 0x7523) }, @@ -160,9 +162,11 @@ static const speed_t ch341_min_rates[] = { * 2 <= div <= 256 if fact = 0, or * 9 <= div <= 256 if fact = 1 */ -static int ch341_get_divisor(speed_t speed) +static int ch341_get_divisor(struct ch341_private *priv) { unsigned int fact, div, clk_div; + speed_t speed = priv->baud_rate; + bool force_fact0 = false; int ps; /* @@ -188,8 +192,12 @@ static int ch341_get_divisor(speed_t speed) clk_div = CH341_CLK_DIV(ps, fact); div = CH341_CLKRATE / (clk_div * speed); + /* Some devices require a lower base clock if ps < 3. */ + if (ps < 3 && (priv->quirks & CH341_QUIRK_LIMITED_PRESCALER)) + force_fact0 = true; + /* Halve base clock (fact = 0) if required. */ - if (div < 9 || div > 255) { + if (div < 9 || div > 255 || force_fact0) { div /= 2; clk_div *= 2; fact = 0; @@ -228,7 +236,7 @@ static int ch341_set_baudrate_lcr(struct usb_device *dev, if (!priv->baud_rate) return -EINVAL; - val = ch341_get_divisor(priv->baud_rate); + val = ch341_get_divisor(priv); if (val < 0) return -EINVAL; @@ -333,6 +341,7 @@ static int ch341_detect_quirks(struct usb_serial_port *port) CH341_REG_BREAK, 0, buffer, size, DEFAULT_TIMEOUT); if (r == -EPIPE) { dev_dbg(&port->dev, "break control not supported\n"); + quirks = CH341_QUIRK_LIMITED_PRESCALER; r = 0; goto out; } -- 2.26.2