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 54C83CCA481 for ; Mon, 13 Jun 2022 11:39:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1355399AbiFMLij (ORCPT ); Mon, 13 Jun 2022 07:38:39 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44628 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1354375AbiFML3Z (ORCPT ); Mon, 13 Jun 2022 07:29:25 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2D6B023155; Mon, 13 Jun 2022 03:43:43 -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 A5190B80E56; Mon, 13 Jun 2022 10:43:41 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 08466C34114; Mon, 13 Jun 2022 10:43:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1655117020; bh=EBGxTKU9AyDLDNJOj98BE0cUlnREUKE+uAzVyapV7TY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=DIIybyd4fd+wZC3thPcu0X1+YNGontymI/20gmF5rcpuTSODx4/9rYQj/KFJ6gf9V XIhSD/WDWWR6QwSRRJifMGmBq5DOWitLi758JT3CunjuDf2mmFDbXgcgrMiKK/Wm5U U7edbWrpv4FEIKu81FMTnajB6Yods5x7pKa+FFKk= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jiri Slaby Subject: [PATCH 5.4 261/411] serial: pch: dont overwrite xmit->buf[0] by x_char Date: Mon, 13 Jun 2022 12:08:54 +0200 Message-Id: <20220613094936.590651186@linuxfoundation.org> X-Mailer: git-send-email 2.36.1 In-Reply-To: <20220613094928.482772422@linuxfoundation.org> References: <20220613094928.482772422@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Jiri Slaby commit d9f3af4fbb1d955bbaf872d9e76502f6e3e803cb upstream. When x_char is to be sent, the TX path overwrites whatever is in the circular buffer at offset 0 with x_char and sends it using pch_uart_hal_write(). I don't understand how this was supposed to work if xmit->buf[0] already contained some character. It must have been lost. Remove this whole pop_tx_x() concept and do the work directly in the callers. (Without printing anything using dev_dbg().) Cc: Fixes: 3c6a483275f4 (Serial: EG20T: add PCH_UART driver) Signed-off-by: Jiri Slaby Link: https://lore.kernel.org/r/20220503080808.28332-1-jslaby@suse.cz Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/pch_uart.c | 27 +++++++-------------------- 1 file changed, 7 insertions(+), 20 deletions(-) --- a/drivers/tty/serial/pch_uart.c +++ b/drivers/tty/serial/pch_uart.c @@ -635,22 +635,6 @@ static int push_rx(struct eg20t_port *pr return 0; } -static int pop_tx_x(struct eg20t_port *priv, unsigned char *buf) -{ - int ret = 0; - struct uart_port *port = &priv->port; - - if (port->x_char) { - dev_dbg(priv->port.dev, "%s:X character send %02x (%lu)\n", - __func__, port->x_char, jiffies); - buf[0] = port->x_char; - port->x_char = 0; - ret = 1; - } - - return ret; -} - static int dma_push_rx(struct eg20t_port *priv, int size) { int room; @@ -900,9 +884,10 @@ static unsigned int handle_tx(struct eg2 fifo_size = max(priv->fifo_size, 1); tx_empty = 1; - if (pop_tx_x(priv, xmit->buf)) { - pch_uart_hal_write(priv, xmit->buf, 1); + if (port->x_char) { + pch_uart_hal_write(priv, &port->x_char, 1); port->icount.tx++; + port->x_char = 0; tx_empty = 0; fifo_size--; } @@ -957,9 +942,11 @@ static unsigned int dma_handle_tx(struct } fifo_size = max(priv->fifo_size, 1); - if (pop_tx_x(priv, xmit->buf)) { - pch_uart_hal_write(priv, xmit->buf, 1); + + if (port->x_char) { + pch_uart_hal_write(priv, &port->x_char, 1); port->icount.tx++; + port->x_char = 0; fifo_size--; }