From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Chen Hu , Heikki Krogerus , Andy Shevchenko Subject: [PATCH 4.9 22/25] serial: 8250_dw: always set baud rate in dw8250_set_termios Date: Tue, 21 Aug 2018 08:21:36 +0200 Message-Id: <20180821055126.054971239@linuxfoundation.org> In-Reply-To: <20180821055124.909865464@linuxfoundation.org> References: <20180821055124.909865464@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Chen Hu commit dfcab6ba573445c703235ab6c83758eec12d7f28 upstream. dw8250_set_termios() doesn't set baud rate if the arg "old ktermios" is NULL. This happens during resume. Call Trace: ... [ 54.928108] dw8250_set_termios+0x162/0x170 [ 54.928114] serial8250_set_termios+0x17/0x20 [ 54.928117] uart_change_speed+0x64/0x160 [ 54.928119] uart_resume_port ... So the baud rate is not restored after S3 and breaks the apps who use UART, for example, console and bluetooth etc. We address this issue by setting the baud rate irrespective of arg "old", just like the drivers for other 8250 IPs. This is tested with Intel Broxton platform. Signed-off-by: Chen Hu Fixes: 4e26b134bd17 ("serial: 8250_dw: clock rate handling for all ACPI platforms") Cc: Heikki Krogerus Cc: stable Reviewed-by: Andy Shevchenko Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/8250/8250_dw.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/drivers/tty/serial/8250/8250_dw.c +++ b/drivers/tty/serial/8250/8250_dw.c @@ -235,7 +235,7 @@ static void dw8250_set_termios(struct ua unsigned int rate; int ret; - if (IS_ERR(d->clk) || !old) + if (IS_ERR(d->clk)) goto out; clk_disable_unprepare(d->clk);