Messages in this thread | | | Date | Mon, 16 Jun 2014 13:40:05 -0400 (EDT) | From | Alan Stern <> | Subject | Re: [PATCH 1/1] PM / Runtime: let rpm_resume fail if rpm disabled and device suspended. |
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On Sat, 14 Jun 2014, Allen Yu wrote:
> --- 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;
For reasons having nothing to do with Allen's suggested change, I wonder if we shouldn't replace this line with something like:
- else if (dev->power.disable_depth == 1 && dev->power.is_suspended + else if (dev->power.disable > 0 && !dev->power.is_suspended && dev->power.runtime_status == RPM_ACTIVE) retval = 1;
It seems that I've been bitten by this several times in the past. When a device is disabled for runtime PM, and more or less permanently stuck in the RPM_ACTIVE state, calls to pm_runtime_resume() or pm_runtime_get_sync() shouldn't fail.
For example, suppose some devices of a certain type support runtime power management but others don't. We naturally want to call pm_runtime_disable() for the ones that don't. But we also want the same driver to work for all the devices, which means that pm_runtime_get_sync() should return success -- otherwise the driver will think that something has gone wrong.
Rafael, what do you think?
Alan Stern
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