[cip-dev] [PATCH] tty: serial: imx: disable irq after suspend

[ben.hutchings@codethink.co.uk (Ben Hutchings)]

On Mon, 2017-11-27 at 16:37 +0100, Maxim Yu. Osipov wrote:
> commit 81b289cc14ba349cc4707cf664aa1c72d7dff1d7 upstream.
> 
> If any key on console is pressed when board is suspended,
> board hangs.

This looks like something that should be applied to stable branches,
not just the CIP 4.4 branch.

Ben.

> Driver's interrupt handler must be guaranteed not to run while
> resume/suspend_noirq() are being executed. See include/linux/pm.h
> for details.
> 
> Tested on i.MX6 based board.
> 
> The idea of this fix is based on commit in official i.MX kernel tree:
> http://git.freescale.com/git/cgit.cgi/imx/linux-2.6-imx.git
> commit 81e8e7d91d81 ("tty: serial: imx: disable irq after suspend")
> 
> Disable rx irq after suspend to avoid interrupt coming in early
> resume.
> 
> Signed-off-by: Fugang Duan <B38611@freescale.com>
> Signed-off-by: Maxim Yu. Osipov <mosipov@ilbers.de>
> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> ---
> ?drivers/tty/serial/imx.c | 2 ++
> ?1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c
> index 016e4be05cec..fae8c83708b1 100644
> --- a/drivers/tty/serial/imx.c
> +++ b/drivers/tty/serial/imx.c
> @@ -2108,6 +2108,7 @@ static int imx_serial_port_suspend(struct
> device *dev)
> ?	serial_imx_enable_wakeup(sport, true);
> ?
> ?	uart_suspend_port(&imx_reg, &sport->port);
> +	disable_irq(sport->port.irq);
> ?
> ?	return 0;
> ?}
> @@ -2121,6 +2122,7 @@ static int imx_serial_port_resume(struct device
> *dev)
> ?	serial_imx_enable_wakeup(sport, false);
> ?
> ?	uart_resume_port(&imx_reg, &sport->port);
> +	enable_irq(sport->port.irq);
> ?
> ?	return 0;
> ?}
-- 
Ben Hutchings
Software Developer, Codethink Ltd.