There are variables(power.may_skip_resume and dev->power.must_resume)
and DPM_FLAG_MAY_SKIP_RESUME flags to control the resume of devices after
a system wide suspend transition.
Setting the DPM_FLAG_MAY_SKIP_RESUME flag means that the driver allows
its "noirq" and "early" resume callbacks to be skipped if the device
can be left in suspend after a system-wide transition into the working
state. PM core determines that the driver's "noirq" and "early" resume
callbacks should be skipped or not with dev_pm_skip_resume() function by
checking power.may_skip_resume variable.
power.must_resume variable is getting set to false in __device_suspend()
function without checking device's DPM_FLAG_MAY_SKIP_RESUME settings.
In problematic scenario, where all the devices in the suspend_late
stage are successful and some device can fail to suspend in
suspend_noirq phase. So some devices successfully suspended in suspend_late
stage are not getting chance to execute __device_suspend_noirq()
to set dev->power.must_resume variable to true and not getting
resumed in early_resume phase.
Add a check for device's DPM_FLAG_MAY_SKIP_RESUME flag before
setting power.must_resume variable in __device_suspend function.
Fixes: 6e176bf8d461 ("PM: sleep: core: Do not skip callbacks in the resume phase")
Signed-off-by: Prasad Sodagudi <[email protected]>
---
V3 -> V4: Remove dev->power.usage_count variable check
V2 -> V3: Format issues patch posting
V1 -> V2: Fixed indentation and commit text to include scenario
drivers/base/power/main.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c
index d568772..50e8ea3 100644
--- a/drivers/base/power/main.c
+++ b/drivers/base/power/main.c
@@ -1642,7 +1642,10 @@ static int __device_suspend(struct device *dev, pm_message_t state, bool async)
}
dev->power.may_skip_resume = true;
- dev->power.must_resume = false;
+ if (dev_pm_test_driver_flags(dev, DPM_FLAG_MAY_SKIP_RESUME))
+ dev->power.must_resume = false;
+ else
+ dev->power.must_resume = true;
dpm_watchdog_set(&wd, dev);
device_lock(dev);
--
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project
On Mon, Aug 23, 2021 at 08:27:50AM -0700, Prasad Sodagudi wrote:
> There are variables(power.may_skip_resume and dev->power.must_resume)
> and DPM_FLAG_MAY_SKIP_RESUME flags to control the resume of devices after
> a system wide suspend transition.
>
> Setting the DPM_FLAG_MAY_SKIP_RESUME flag means that the driver allows
> its "noirq" and "early" resume callbacks to be skipped if the device
> can be left in suspend after a system-wide transition into the working
> state. PM core determines that the driver's "noirq" and "early" resume
> callbacks should be skipped or not with dev_pm_skip_resume() function by
> checking power.may_skip_resume variable.
>
> power.must_resume variable is getting set to false in __device_suspend()
> function without checking device's DPM_FLAG_MAY_SKIP_RESUME settings.
> In problematic scenario, where all the devices in the suspend_late
> stage are successful and some device can fail to suspend in
> suspend_noirq phase. So some devices successfully suspended in suspend_late
> stage are not getting chance to execute __device_suspend_noirq()
> to set dev->power.must_resume variable to true and not getting
> resumed in early_resume phase.
>
> Add a check for device's DPM_FLAG_MAY_SKIP_RESUME flag before
> setting power.must_resume variable in __device_suspend function.
>
> Fixes: 6e176bf8d461 ("PM: sleep: core: Do not skip callbacks in the resume phase")
> Signed-off-by: Prasad Sodagudi <[email protected]>
> ---
> V3 -> V4: Remove dev->power.usage_count variable check
> V2 -> V3: Format issues patch posting
> V1 -> V2: Fixed indentation and commit text to include scenario
> drivers/base/power/main.c | 5 ++++-
> 1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c
> index d568772..50e8ea3 100644
> --- a/drivers/base/power/main.c
> +++ b/drivers/base/power/main.c
> @@ -1642,7 +1642,10 @@ static int __device_suspend(struct device *dev, pm_message_t state, bool async)
> }
>
> dev->power.may_skip_resume = true;
> - dev->power.must_resume = false;
> + if (dev_pm_test_driver_flags(dev, DPM_FLAG_MAY_SKIP_RESUME))
> + dev->power.must_resume = false;
> + else
> + dev->power.must_resume = true;
>
> dpm_watchdog_set(&wd, dev);
> device_lock(dev);
Seems sane, Rafael, any comments?
thanks,
greg k-h
On Mon, Aug 23, 2021 at 5:28 PM Prasad Sodagudi <[email protected]> wrote:
>
> There are variables(power.may_skip_resume and dev->power.must_resume)
> and DPM_FLAG_MAY_SKIP_RESUME flags to control the resume of devices after
> a system wide suspend transition.
>
> Setting the DPM_FLAG_MAY_SKIP_RESUME flag means that the driver allows
> its "noirq" and "early" resume callbacks to be skipped if the device
> can be left in suspend after a system-wide transition into the working
> state. PM core determines that the driver's "noirq" and "early" resume
> callbacks should be skipped or not with dev_pm_skip_resume() function by
> checking power.may_skip_resume variable.
>
> power.must_resume variable is getting set to false in __device_suspend()
> function without checking device's DPM_FLAG_MAY_SKIP_RESUME settings.
> In problematic scenario, where all the devices in the suspend_late
> stage are successful and some device can fail to suspend in
> suspend_noirq phase. So some devices successfully suspended in suspend_late
> stage are not getting chance to execute __device_suspend_noirq()
> to set dev->power.must_resume variable to true and not getting
> resumed in early_resume phase.
>
> Add a check for device's DPM_FLAG_MAY_SKIP_RESUME flag before
> setting power.must_resume variable in __device_suspend function.
>
> Fixes: 6e176bf8d461 ("PM: sleep: core: Do not skip callbacks in the resume phase")
> Signed-off-by: Prasad Sodagudi <[email protected]>
> ---
> V3 -> V4: Remove dev->power.usage_count variable check
> V2 -> V3: Format issues patch posting
> V1 -> V2: Fixed indentation and commit text to include scenario
> drivers/base/power/main.c | 5 ++++-
> 1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c
> index d568772..50e8ea3 100644
> --- a/drivers/base/power/main.c
> +++ b/drivers/base/power/main.c
> @@ -1642,7 +1642,10 @@ static int __device_suspend(struct device *dev, pm_message_t state, bool async)
> }
>
> dev->power.may_skip_resume = true;
> - dev->power.must_resume = false;
> + if (dev_pm_test_driver_flags(dev, DPM_FLAG_MAY_SKIP_RESUME))
> + dev->power.must_resume = false;
> + else
> + dev->power.must_resume = true;
Why don't you write it as
dev->power.must_resume = !dev_pm_test_driver_flags(dev,
DPM_FLAG_MAY_SKIP_RESUME);
>
> dpm_watchdog_set(&wd, dev);
> device_lock(dev);
> --
> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
> a Linux Foundation Collaborative Project
>
On Fri, Aug 27, 2021 at 10:58 AM Greg KH <[email protected]> wrote:
>
> On Mon, Aug 23, 2021 at 08:27:50AM -0700, Prasad Sodagudi wrote:
> > There are variables(power.may_skip_resume and dev->power.must_resume)
> > and DPM_FLAG_MAY_SKIP_RESUME flags to control the resume of devices after
> > a system wide suspend transition.
> >
> > Setting the DPM_FLAG_MAY_SKIP_RESUME flag means that the driver allows
> > its "noirq" and "early" resume callbacks to be skipped if the device
> > can be left in suspend after a system-wide transition into the working
> > state. PM core determines that the driver's "noirq" and "early" resume
> > callbacks should be skipped or not with dev_pm_skip_resume() function by
> > checking power.may_skip_resume variable.
> >
> > power.must_resume variable is getting set to false in __device_suspend()
> > function without checking device's DPM_FLAG_MAY_SKIP_RESUME settings.
> > In problematic scenario, where all the devices in the suspend_late
> > stage are successful and some device can fail to suspend in
> > suspend_noirq phase. So some devices successfully suspended in suspend_late
> > stage are not getting chance to execute __device_suspend_noirq()
> > to set dev->power.must_resume variable to true and not getting
> > resumed in early_resume phase.
> >
> > Add a check for device's DPM_FLAG_MAY_SKIP_RESUME flag before
> > setting power.must_resume variable in __device_suspend function.
> >
> > Fixes: 6e176bf8d461 ("PM: sleep: core: Do not skip callbacks in the resume phase")
> > Signed-off-by: Prasad Sodagudi <[email protected]>
> > ---
> > V3 -> V4: Remove dev->power.usage_count variable check
> > V2 -> V3: Format issues patch posting
> > V1 -> V2: Fixed indentation and commit text to include scenario
> > drivers/base/power/main.c | 5 ++++-
> > 1 file changed, 4 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c
> > index d568772..50e8ea3 100644
> > --- a/drivers/base/power/main.c
> > +++ b/drivers/base/power/main.c
> > @@ -1642,7 +1642,10 @@ static int __device_suspend(struct device *dev, pm_message_t state, bool async)
> > }
> >
> > dev->power.may_skip_resume = true;
> > - dev->power.must_resume = false;
> > + if (dev_pm_test_driver_flags(dev, DPM_FLAG_MAY_SKIP_RESUME))
> > + dev->power.must_resume = false;
> > + else
> > + dev->power.must_resume = true;
> >
> > dpm_watchdog_set(&wd, dev);
> > device_lock(dev);
>
> Seems sane, Rafael, any comments?
Yup, please see my response:
https://lore.kernel.org/linux-pm/CAJZ5v0hAuZmaB6j4qA7P43J4TshBrYa8UsX3KtH7hkxWZPU2wA@mail.gmail.com/T/#t
Cheers!