On 4 October 2018 at 11:08, Rafael J. Wysocki <r...@rjwysocki.net> wrote:
> From: Rafael J. Wysocki <rafael.j.wyso...@intel.com>
>
> If __device_suspend() returns early on an error or pending wakeup
> and the power.direct_complete flag has been set for the device
> already, the subsequent device_resume() will be confused by it
> and it will call pm_runtime_enable() incorrectly, as runtime PM
> has not been disabled for the device by __device_suspend().
I think it would be fair to mention that is related to the async
suspend path, in dpm_suspend().
>
> To avoid that, clear power.direct_complete if __device_suspend()
> is not going to disable runtime PM for the device before returning.
Overall, by looking at the behavior in dpm_suspend() of async
suspended devices, it does look a bit fragile to me.
My worries is that we put asynced suspended devices in the
dpm_suspended_list, no matter if the device was successfully suspended
or not. This differs from the no-async path.
In the long run, maybe we should change that instead?
>
> Fixes: aae4518b3124 (PM / sleep: Mechanism to avoid resuming
> runtime-suspended devices unnecessarily)
> Reported-by: Al Cooper <alcoop...@gmail.com>
> Cc: 3.16+ <sta...@vger.kernel.org> # 3.16+
> Signed-off-by: Rafael J. Wysocki <rafael.j.wyso...@intel.com>
Reviewed-by: Ulf Hansson <ulf.hans...@linaro.org>
Kind regards
Uffe
> ---
> drivers/base/power/main.c | 5 ++++-
> 1 file changed, 4 insertions(+), 1 deletion(-)
>
> Index: linux-pm/drivers/base/power/main.c
> ===================================================================
> --- linux-pm.orig/drivers/base/power/main.c
> +++ linux-pm/drivers/base/power/main.c
> @@ -1713,8 +1713,10 @@ static int __device_suspend(struct devic
>
> dpm_wait_for_subordinate(dev, async);
>
> - if (async_error)
> + if (async_error) {
> + dev->power.direct_complete = false;
> goto Complete;
> + }
>
> /*
> * If a device configured to wake up the system from sleep states
> @@ -1726,6 +1728,7 @@ static int __device_suspend(struct devic
> pm_wakeup_event(dev, 0);
>
> if (pm_wakeup_pending()) {
> + dev->power.direct_complete = false;
> async_error = -EBUSY;
> goto Complete;
> }
>
