From nobody Wed Dec 17 09:15:07 2025 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 7367BC32796 for ; Tue, 23 Aug 2022 10:47:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1355977AbiHWKqE (ORCPT ); Tue, 23 Aug 2022 06:46:04 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46718 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1355426AbiHWKiX (ORCPT ); Tue, 23 Aug 2022 06:38:23 -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 DB3A1A720F; Tue, 23 Aug 2022 02:07:45 -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 3AFE5B81C65; Tue, 23 Aug 2022 09:07:44 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id A6F92C433C1; Tue, 23 Aug 2022 09:07:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1661245663; bh=5Yabsf9P9O//Eym2yywOLLQ57DVHSg+BZbAaS79Jszs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=KL6NdvaMjez7UwcLEg3oYA/enpqul4I7Czn6q7dEaa7UbHCW428ZtSNdvRC+MrgZZ tnZPKU3pfHoAzrtg+CFMbH1TpBMjKoHG+qiblr2J0PhrGEaA6+8Drw9xoXsx1/xnwv dnWINX608e0nBx6wV4ArJ8/EwKFmpN0VVpEnNd4w= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Andy Shevchenko , =?UTF-8?q?Ilpo=20J=C3=A4rvinen?= , Sasha Levin Subject: [PATCH 4.19 150/287] serial: 8250_dw: Store LSR into lsr_saved_flags in dw8250_tx_wait_empty() Date: Tue, 23 Aug 2022 10:25:19 +0200 Message-Id: <20220823080105.646601472@linuxfoundation.org> X-Mailer: git-send-email 2.37.2 In-Reply-To: <20220823080100.268827165@linuxfoundation.org> References: <20220823080100.268827165@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Ilpo J=C3=A4rvinen [ Upstream commit af14f3007e2dca0d112f10f6717ba43093f74e81 ] Make sure LSR flags are preserved in dw8250_tx_wait_empty(). This function is called from a low-level out function and therefore cannot call serial_lsr_in() as it would lead to infinite recursion. It is borderline if the flags need to be saved here at all since this code relates to writing LCR register which usually implies no important characters should be arriving. Fixes: 914eaf935ec7 ("serial: 8250_dw: Allow TX FIFO to drain before writin= g to UART_LCR") Reviewed-by: Andy Shevchenko Signed-off-by: Ilpo J=C3=A4rvinen Link: https://lore.kernel.org/r/20220608095431.18376-7-ilpo.jarvinen@linux.= intel.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin --- drivers/tty/serial/8250/8250_dw.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/tty/serial/8250/8250_dw.c b/drivers/tty/serial/8250/82= 50_dw.c index c73d0eddd9b8..cc9d1f416db8 100644 --- a/drivers/tty/serial/8250/8250_dw.c +++ b/drivers/tty/serial/8250/8250_dw.c @@ -140,12 +140,15 @@ static void dw8250_check_lcr(struct uart_port *p, int= value) /* Returns once the transmitter is empty or we run out of retries */ static void dw8250_tx_wait_empty(struct uart_port *p) { + struct uart_8250_port *up =3D up_to_u8250p(p); unsigned int tries =3D 20000; unsigned int delay_threshold =3D tries - 1000; unsigned int lsr; =20 while (tries--) { lsr =3D readb (p->membase + (UART_LSR << p->regshift)); + up->lsr_saved_flags |=3D lsr & LSR_SAVE_FLAGS; + if (lsr & UART_LSR_TEMT) break; =20 --=20 2.35.1