From patchwork Mon Feb 28 17:25:05 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 547075 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 3EB7AC433EF for ; Mon, 28 Feb 2022 17:54:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233606AbiB1Rz0 (ORCPT ); Mon, 28 Feb 2022 12:55:26 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45776 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240543AbiB1RyX (ORCPT ); Mon, 28 Feb 2022 12:54:23 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 098A789309; Mon, 28 Feb 2022 09:42:27 -0800 (PST) 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 dfw.source.kernel.org (Postfix) with ESMTPS id 8AF5F614CC; Mon, 28 Feb 2022 17:42:26 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id A0CB6C340E7; Mon, 28 Feb 2022 17:42:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1646070146; bh=ZNL+mEBR4XMCq4oZHwhquU3SqBWtFw4lFumbGLpqAdE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=SsJ5PWI4FD6UrDmEeOMxYUZ+NWODlu+NR/TaxnOise9jPt5jL+PrDkY9eFwiDVI/v RJWE1jMxgfiyOQtTttfCjAIewXKa4OzRFxmECCfHl7xAn+tnobfYzTcRQa8MHl5ufd fmP3+8F6HHcxA2186SNL9kJ8CMPh/UFyfI6BxfnM= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Daniel Starke Subject: [PATCH 5.15 131/139] tty: n_gsm: fix wrong tty control line for flow control Date: Mon, 28 Feb 2022 18:25:05 +0100 Message-Id: <20220228172401.455830521@linuxfoundation.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220228172347.614588246@linuxfoundation.org> References: <20220228172347.614588246@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: daniel.starke@siemens.com commit c19d93542a6081577e6da9bf5e887979c72e80c1 upstream. tty flow control is handled via gsmtty_throttle() and gsmtty_unthrottle(). Both functions propagate the outgoing hardware flow control state to the remote side via MSC (modem status command) frames. The local state is taken from the RTS (ready to send) flag of the tty. However, RTS gets mapped to DTR (data terminal ready), which is wrong. This patch corrects this by mapping RTS to RTS. Fixes: e1eaea46bb40 ("tty: n_gsm line discipline") Cc: stable@vger.kernel.org Signed-off-by: Daniel Starke Link: https://lore.kernel.org/r/20220218073123.2121-5-daniel.starke@siemens.com Signed-off-by: Greg Kroah-Hartman --- drivers/tty/n_gsm.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) --- a/drivers/tty/n_gsm.c +++ b/drivers/tty/n_gsm.c @@ -3180,9 +3180,9 @@ static void gsmtty_throttle(struct tty_s if (dlci->state == DLCI_CLOSED) return; if (C_CRTSCTS(tty)) - dlci->modem_tx &= ~TIOCM_DTR; + dlci->modem_tx &= ~TIOCM_RTS; dlci->throttled = true; - /* Send an MSC with DTR cleared */ + /* Send an MSC with RTS cleared */ gsmtty_modem_update(dlci, 0); } @@ -3192,9 +3192,9 @@ static void gsmtty_unthrottle(struct tty if (dlci->state == DLCI_CLOSED) return; if (C_CRTSCTS(tty)) - dlci->modem_tx |= TIOCM_DTR; + dlci->modem_tx |= TIOCM_RTS; dlci->throttled = false; - /* Send an MSC with DTR set */ + /* Send an MSC with RTS set */ gsmtty_modem_update(dlci, 0); }