linux-kernel - Re: [PATCH] BUG: atmel_serial: Interrupts not disabled on close

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Date:   Mon, 12 Sep 2016 17:22:58 +0200
From:   Nicolas Ferre <nicolas.ferre@...el.com>
To:     Richard Genoud <richard.genoud@...il.com>,
        Uwe Kleine-König <u.kleine-koenig@...gutronix.de>,
        "Greg Kroah-Hartman" <gregkh@...uxfoundation.org>
CC:     Alexandre Belloni <alexandre.belloni@...e-electrons.com>,
        Cyrille Pitchen <cyrille.pitchen@...el.com>,
        <linux-serial@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <linux-arm-kernel@...ts.infradead.org>
Subject: Re: [PATCH] BUG: atmel_serial: Interrupts not disabled on close

Le 12/09/2016 à 15:34, Richard Genoud a écrit :
> Since commit 18dfef9c7f87 ("serial: atmel: convert to irq handling
> provided mctrl-gpio"), interrupts from GPIOs are not disabled any more
> when the serial port is closed, leading to an oops when the one of the
> input pin is toggled (CTS/DSR/DCD/RNG).
> 
> This is only the case if those pins are used as GPIOs, i.e. declared
> like that:
> usart1: serial@...20000 {
>         /* CTS and DTS will be handled by GPIO */
>         status = "okay";
>         rts-gpios = <&pioB 17 GPIO_ACTIVE_LOW>;
>         cts-gpios = <&pioB 16 GPIO_ACTIVE_LOW>;
>         dtr-gpios = <&pioB 14 GPIO_ACTIVE_LOW>;
>         dsr-gpios = <&pioC 31 GPIO_ACTIVE_LOW>;
>         rng-gpios = <&pioB 12 GPIO_ACTIVE_LOW>;
>         dcd-gpios = <&pioB 15 GPIO_ACTIVE_LOW>;
> };
> 
> That's because modem interrupts used to be freed in atmel_shutdown().
> After commit 18dfef9c7f87 ("serial: atmel: convert to irq handling
> provided mctrl-gpio"), this code was just removed.
> Calling atmel_disable_ms() disables the interrupts and everything works
> fine again.
> 
> Tested on at91sam9g35-cm
> 
> (This patch doesn't apply on -stable kernels, fixes for 4.4 and 4.7 will
> be sent after this one is applied.)
> 
> Signed-off-by: Richard Genoud <richard.genoud@...il.com>
> Fixes: 18dfef9c7f87 ("serial: atmel: convert to irq handling provided mctrl-gpio")

I thinks it's a bit late for "4.8-fixes".

Greg, tell me if you want that I add the Cc: stable tag to this patch
(as advised by Uwe) and re-send?

Acked-by: Nicolas Ferre <nicolas.ferre@...el.com>

Thanks Richard!

Best regards,

> ---
>  drivers/tty/serial/atmel_serial.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c
> index 2eaa18ddef61..8bbde52db376 100644
> --- a/drivers/tty/serial/atmel_serial.c
> +++ b/drivers/tty/serial/atmel_serial.c
> @@ -1929,6 +1929,9 @@ static void atmel_shutdown(struct uart_port *port)
>  {
>  	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
>  
> +	/* Disable modem control lines interrupts */
> +	atmel_disable_ms(port);
> +
>  	/* Disable interrupts at device level */
>  	atmel_uart_writel(port, ATMEL_US_IDR, -1);
>  
> @@ -1979,8 +1982,6 @@ static void atmel_shutdown(struct uart_port *port)
>  	 */
>  	free_irq(port->irq, port);
>  
> -	atmel_port->ms_irq_enabled = false;
> -
>  	atmel_flush_buffer(port);
>  }
>  
> 


-- 
Nicolas Ferre