On Wed, 15 Jul 2015, Tomeu Vizoso wrote:
> If a suitable prepare callback cannot be found for a given device and
> its driver has no PM callbacks at all, assume that it can go direct to
> complete when the system goes to sleep.
>
> The reason for this is that there's lots of devices in a system that do
> no PM at all and there's no reason for them to prevent their ancestors
> to do direct_complete if they can support it.
>
> Signed-off-by: Tomeu Vizoso <tomeu.viz...@collabora.com>
> ---
>
> drivers/base/power/main.c | 17 +++++++++++++++++
> 1 file changed, 17 insertions(+)
>
> diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c
> index 1710c26ba097..edda3f233c7c 100644
> --- a/drivers/base/power/main.c
> +++ b/drivers/base/power/main.c
> @@ -1540,6 +1540,21 @@ int dpm_suspend(pm_message_t state)
> return error;
> }
>
> +static bool driver_has_no_pm_callbacks(struct device_driver *drv)
> +{
> + if (!drv->pm)
> + return true;
> +
> + return !drv->pm->prepare &&
> + !drv->pm->suspend &&
> + !drv->pm->suspend_late &&
> + !drv->pm->suspend_noirq &&
> + !drv->pm->resume_noirq &&
> + !drv->pm->resume_early &&
> + !drv->pm->resume &&
> + !drv->pm->complete;
> +}
This isn't exactly what I meant. We also need to check the dev_pm_ops
fields in dev->pm_domain, dev->type, dev->class, and dev->bus. Only if
_all_ of these callbacks are missing should we use direct_complete.
Alan Stern
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