Messages in this thread | | | From | "Rafael J. Wysocki" <> | Date | Fri, 27 Aug 2021 14:21:00 +0200 | Subject | Re: [PATCH v4] PM: sleep: core: Avoid setting power.must_resume to false |
| |
On Fri, Aug 27, 2021 at 10:58 AM Greg KH <gregkh@linuxfoundation.org> 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 <psodagud@codeaurora.org> > > --- > > 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!
| |