From nobody Sun Dec 14 06:20:41 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 EC285C00140 for ; Mon, 15 Aug 2022 19:32:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344851AbiHOTbt (ORCPT ); Mon, 15 Aug 2022 15:31:49 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54242 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1344516AbiHOT04 (ORCPT ); Mon, 15 Aug 2022 15:26:56 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 64ED25A3D3; Mon, 15 Aug 2022 11:42:42 -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 dfw.source.kernel.org (Postfix) with ESMTPS id B1347611C2; Mon, 15 Aug 2022 18:42:41 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9FCF6C433C1; Mon, 15 Aug 2022 18:42:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1660588961; bh=TZ2I0orKzVsErbjWyCR70Fk0ZaBl7NXIQBB05th5cEQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=VUWlGyOHKOXDkGTHk8nIHIsTDpyiusFC83LTE9yYCQugOXUu/OyKA2c5RHnFvGWKa ya0swIv6Y/SbWUPxitETbVbiIjD3ub9njJIURsqI/u4KDVeq+YKtafrsJKdmnAxlk/ WR8UCYTTSIhhGOE6fqGgmXaqjJg0m+Srg62mHdFo= 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 5.15 570/779] serial: 8250_dw: Store LSR into lsr_saved_flags in dw8250_tx_wait_empty() Date: Mon, 15 Aug 2022 20:03:34 +0200 Message-Id: <20220815180401.697120685@linuxfoundation.org> X-Mailer: git-send-email 2.37.2 In-Reply-To: <20220815180337.130757997@linuxfoundation.org> References: <20220815180337.130757997@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 49559731bbcf..ace221afeb03 100644 --- a/drivers/tty/serial/8250/8250_dw.c +++ b/drivers/tty/serial/8250/8250_dw.c @@ -124,12 +124,15 @@ 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