On Sat, 14 Jun 2014, Allen Yu wrote: > dev->power.is_suspended is set after core suspends device during system > suspend. > This flag mostly means device is not operational (all I/O been quiesced, no > more > data read or write acceptible, etc.), hence it's dangerous to access hardware > if > device is suspended even though runtime PM status is RPM_ACTIVE. > > In turn, we should allow device to be accessed in case device is *not* > suspended > and runtime PM status is RPM_ACTIVE, even if runtime PM disabled. This corner > case > can happen to a device in a generic PM domain if the domain is not powered > off while > preparing for a system-wide power transition.
I don't understand. Even if the PM domain isn't powered off, the device's is_suspended flag will still be set by __device_suspend(). > In this case, runtime PM status will > be set to RPM_ACTIVE and then runtime PM is disabled. After that, device > driver may > call pm_runtime_get_sync() and rpm_resume() should return 1, because the > device is > still active as long as not been suspended. Isn't that what the existing code does already? Your patch seems to change it so that it _doesn't_ behave the way you want. > Signed-off-by: Allen Yu <all...@nvidia.com> > --- > drivers/base/power/runtime.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/base/power/runtime.c b/drivers/base/power/runtime.c > index 67c7938..39885f1 100644 > --- a/drivers/base/power/runtime.c > +++ b/drivers/base/power/runtime.c > @@ -608,7 +608,7 @@ static int rpm_resume(struct device *dev, int rpmflags) > repeat: > if (dev->power.runtime_error) > retval = -EINVAL; > - else if (dev->power.disable_depth == 1 && dev->power.is_suspended > + else if (dev->power.disable_depth == 1 && !dev->power.is_suspended > && dev->power.runtime_status == RPM_ACTIVE) > retval = 1; Alan Stern -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
