Re: [RESEND PATCH 1/2] spi: rockchip: Convert to late and early system PM callbacks

From: Doug Anderson
Date: Fri Oct 13 2017 - 11:32:21 EST


Hi,

On Fri, Oct 13, 2017 at 3:41 AM, Jeffy Chen <jeffy.chen@xxxxxxxxxxxxxx> wrote:
> Currently we are suspending the spi master in it's ->suspend callback,
> which is racy as some other drivers may still want to transmit messages
> on the bus(e.g. spi based pwm backlight).
>
> Convert to late and early system PM callbacks to avoid the race.
>
> Signed-off-by: Jeffy Chen <jeffy.chen@xxxxxxxxxxxxxx>
> ---
>
> drivers/spi/spi-rockchip.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)

It shouldn't hurt to do this, but I'm curious if you did any digging
about why this happens? As I understood it suspend order is supposed
to be opposite of probe order. Thus anything that was able to get a
reference to the cros-ec PWM at its probe time should get suspended
before cros-ec suspends.


-Doug