Messages in this thread | | | Date | Fri, 6 Aug 2021 17:16:21 +0200 | From | Greg KH <> | Subject | Re: [PATCH] PM: sleep: core: Avoid setting power.must_resume to false |
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On Fri, Aug 06, 2021 at 08:07:08AM -0700, psodagud@codeaurora.org wrote: > On 2021-08-03 10:16, Greg KH wrote: > > On Mon, Jul 26, 2021 at 08:24:34AM -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 and > > > dev->power.usage_count variables. This is leading to failure to call > > > resume handler for some of the devices suspended in early suspend > > > phase. > > > So check device's DPM_FLAG_MAY_SKIP_RESUME flag before > > > setting power.must_resume variable. > > > > > > Signed-off-by: Prasad Sodagudi <psodagud@codeaurora.org> > > > --- > > > drivers/base/power/main.c | 6 +++++- > > > 1 file changed, 5 insertions(+), 1 deletion(-) > > > > > > diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c > > > index d568772..8eebc4d 100644 > > > --- a/drivers/base/power/main.c > > > +++ b/drivers/base/power/main.c > > > @@ -1642,7 +1642,11 @@ 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 ((atomic_read(&dev->power.usage_count) <= 1) && > > > + (dev_pm_test_driver_flags(dev, DPM_FLAG_MAY_SKIP_RESUME))) > > > > What is preventing that atomic value from changing _right_ after you > > just read this? > > > > and very odd indentation, checkpatch didn't complain about this? > Sure. I will fix indentation problem once Rafael reviewed this patch.
Neither of us can take this as-is, so why wait?
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