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=-8.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,USER_AGENT_MUTT autolearn=unavailable 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 46182C04AAA for ; Mon, 13 May 2019 13:51:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2200720657 for ; Mon, 13 May 2019 13:51:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729861AbfEMNvR (ORCPT ); Mon, 13 May 2019 09:51:17 -0400 Received: from sauhun.de ([88.99.104.3]:40712 "EHLO pokefinder.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729465AbfEMNvR (ORCPT ); Mon, 13 May 2019 09:51:17 -0400 Received: from localhost (p54B3324F.dip0.t-ipconnect.de [84.179.50.79]) by pokefinder.org (Postfix) with ESMTPSA id 745163E42F7; Mon, 13 May 2019 15:51:14 +0200 (CEST) Date: Mon, 13 May 2019 15:51:14 +0200 From: Wolfram Sang To: "George G. Davis" Cc: Eugeniu Rosca , Geert Uytterhoeven , Greg Kroah-Hartman , Jiri Slaby , "open list:SERIAL DRIVERS" , open list , Simon Horman , Chris Brandt , Wolfram Sang , Ulrich Hecht , Andy Lowe , Linux-Renesas , OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS , Magnus Damm , Rob Herring , Mark Rutland , "George G. Davis" Subject: Re: [PATCH] serial: sh-sci: disable DMA for uart_console Message-ID: <20190513135114.GA20443@kunai> References: <20190506194233.GA32430@vmlxhi-102.adit-jv.com> <1557413011-1662-1-git-send-email-george_davis@mentor.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="d6Gm4EdcadzBjdND" Content-Disposition: inline In-Reply-To: <1557413011-1662-1-git-send-email-george_davis@mentor.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --d6Gm4EdcadzBjdND Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Thu, May 09, 2019 at 10:43:30AM -0400, George G. Davis wrote: > As noted in commit 84b40e3b57ee ("serial: 8250: omap: Disable DMA for > console UART"), UART console lines use low-level PIO only access functions > which will conflict with use of the line when DMA is enabled, e.g. when > the console line is also used for systemd messages. So disable DMA > support for UART console lines. >=20 > Fixes: https://patchwork.kernel.org/patch/10929511/ > Reported-by: Michael Rodin > Cc: Eugeniu Rosca > Signed-off-by: George G. Davis > --- > drivers/tty/serial/sh-sci.c | 3 +++ > 1 file changed, 3 insertions(+) >=20 > diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c > index 3cd139752d3f..885b56b1d4e4 100644 > --- a/drivers/tty/serial/sh-sci.c > +++ b/drivers/tty/serial/sh-sci.c > @@ -1557,6 +1557,9 @@ static void sci_request_dma(struct uart_port *port) > =20 > dev_dbg(port->dev, "%s: port %d\n", __func__, port->line); > =20 > + if (uart_console(port)) > + return; /* Cannot use DMA on console */ Minor nit: maybe the comment can be made more specific? /* * DMA on console may interfere with Kernel log messages which use * plain putchar(). So, simply don't use it with a console. */ Other than that: Reviewed-by: Wolfram Sang Much better than dropping the properties, as Geert noted. --d6Gm4EdcadzBjdND Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIyBAABCgAdFiEEOZGx6rniZ1Gk92RdFA3kzBSgKbYFAlzZdk0ACgkQFA3kzBSg KbbUJg/0D+EF6AyzLCGEPsV3puYcRKlpa9CGvd9V4bDHTn0Ft4v3pq+VR8CZg8Xc GGERKTh4+uu5SAFeYT9ZamkFLTBcyrzJ+qJWVuSmkZROJg6OlRn10tMV5Vw1L5PY O4IHapY707vQb6c9Sey6xoF15n7sKWD3HeoNyTDKwncPPwdDulsri2Q0WLIwrq3T L5T+wDTVlAW+Vbw4TA3FBZVjWjWthT85hpTZW802YWyA+ZJMwS678BU6eL7UZFwN +/raK/zqcTfyoY3vk03nG82BIQeZ4IVenLo7F9eXSYUY2d0JBzBbPqJOqINy2pbD j1eaOap+xS4TmlDNRSI9mIJb75AQXNaVz47P/tCQmLvJnNsFXREtzTlKT5pk489k FNQ0S1wpAf2clOUr+of53LKKnK2nS5vtWnoTcIE+g8dOztRDn2WkW20Ly0TgF8e1 UPPOeoNkdGzeHHOQh0CA4yOlaKef0CV/WpxLTtRmlP+hPkyQOSbyYeVkipVd7TWu wwVBCSkIzUPnv6Ybmrrp0B0T6F5pZ3+c0Gy9SZH895dzYZF3ybnAqrRQ/T62UBvV 7birU3vYq5sr4pyoQtnsrF2pAfcJecMcGem5WeQlbAlhRUkq7k89BJ91FNf73blL QsZr8CAATc7aCb/7Cj8O38Ify07O45dNe/djQ25GyP+rfrL+OA== =7vLz -----END PGP SIGNATURE----- --d6Gm4EdcadzBjdND--