On Thu, 23 Jun 2011, Rafael J. Wysocki wrote:
> > > Index: linux-2.6/drivers/base/power/runtime.c
> > > ===================================================================
> > > --- linux-2.6.orig/drivers/base/power/runtime.c
> > > +++ linux-2.6/drivers/base/power/runtime.c
> > > @@ -455,12 +455,14 @@ static int rpm_resume(struct device *dev
> > > dev_dbg(dev, "%s flags 0x%x\n", __func__, rpmflags);
> > >
> > > repeat:
> > > - if (dev->power.runtime_error)
> > > + if (dev->power.runtime_error) {
> > > retval = -EINVAL;
> > > - else if (dev->power.disable_depth > 0)
> > > - retval = -EAGAIN;
> > > - if (retval)
> > > goto out;
> > > + } else if (dev->power.disable_depth > 0) {
> > > + if (!(rpmflags & RPM_GET_PUT))
> > > + retval = -EAGAIN;
> >
> > Do you also want to check the current status? If it isn't RPM_ACTIVE
> > then perhaps you should return an error.
>
> That depends on whether or not we want RPM_ACTIVE to have any meaning for
> devices whose power.disable_depth is nonzero. My opinion is that if
> power.disable_depth is nonzero, the runtime PM status of the device
> shouldn't matter (it may be changed on the fly in ways that need not
> reflect the real status).
Then maybe this disable_depth > 0 case should return something other
than 0. Something new, like -EACCES. That way the caller would
realize something strange was going on but wouldn't have to treat the
situation as an error.
After all, the return value from pm_runtime_get_sync() is documented to
be the error code for the underlying pm_runtime_resume(). It doesn't
refer to the increment operation -- that always succeeds.
Alan Stern
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