| Message ID | 1368443127-9636-1-git-send-email-mika.westerberg@linux.intel.com (mailing list archive) |
|---|---|
| State | Rejected, archived |
| Headers | show |
On Monday, May 13, 2013 02:05:27 PM Mika Westerberg wrote: > If the device is using autosuspend we should honor that and call > pm_runtime_autosuspend() instead of pm_runtime_suspend(). Failing to do so > causes the device to be suspended immediately even though it expects to be > suspended only when the autosuspend delay is expired. > > Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com> > --- > drivers/base/power/generic_ops.c | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > > diff --git a/drivers/base/power/generic_ops.c b/drivers/base/power/generic_ops.c > index bfd898b..19786ca 100644 > --- a/drivers/base/power/generic_ops.c > +++ b/drivers/base/power/generic_ops.c > @@ -29,7 +29,10 @@ int pm_generic_runtime_idle(struct device *dev) > return ret; > } > > - pm_runtime_suspend(dev); > + if (dev->power.use_autosuspend) > + pm_runtime_autosuspend(dev); > + else > + pm_runtime_suspend(dev); > return 0; First of all, this is racy (power.use_autosuspend shoud be accessed under power.lock). Second, this is not the only place we'd need to make this change (the analogous function for PCI is one example, but there may be others). Finally, I'm not sure how to address this problem in general. It may be better to simply modify rpm_idle() and remove pm_generic_runtime_idle() etc. entirely. I'll have a look at that, thanks for pointing out the problem. Rafael > } > EXPORT_SYMBOL_GPL(pm_generic_runtime_idle); >
On Monday, May 13, 2013 01:50:18 PM Rafael J. Wysocki wrote: > On Monday, May 13, 2013 02:05:27 PM Mika Westerberg wrote: > > If the device is using autosuspend we should honor that and call > > pm_runtime_autosuspend() instead of pm_runtime_suspend(). Failing to do so > > causes the device to be suspended immediately even though it expects to be > > suspended only when the autosuspend delay is expired. > > > > Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com> > > --- > > drivers/base/power/generic_ops.c | 5 ++++- > > 1 file changed, 4 insertions(+), 1 deletion(-) > > > > diff --git a/drivers/base/power/generic_ops.c b/drivers/base/power/generic_ops.c > > index bfd898b..19786ca 100644 > > --- a/drivers/base/power/generic_ops.c > > +++ b/drivers/base/power/generic_ops.c > > @@ -29,7 +29,10 @@ int pm_generic_runtime_idle(struct device *dev) > > return ret; > > } > > > > - pm_runtime_suspend(dev); > > + if (dev->power.use_autosuspend) > > + pm_runtime_autosuspend(dev); > > + else > > + pm_runtime_suspend(dev); > > return 0; > > First of all, this is racy (power.use_autosuspend shoud be accessed under > power.lock). > > Second, this is not the only place we'd need to make this change (the analogous > function for PCI is one example, but there may be others). > > Finally, I'm not sure how to address this problem in general. It may be better > to simply modify rpm_idle() and remove pm_generic_runtime_idle() etc. entirely. > > I'll have a look at that, thanks for pointing out the problem. I'm not sure if the core is the right place to address this, because it's not entirely clear if all drivers using autosuspend will have the same policy with respect to pm_runtime_idle() (i.e. to avoid suspending immediately if the suspend delay timer is active). In my opinion it'd be better to address that in the driver by adding a .runtime_idle() callback executing pm_runtime_autosuspend(dev) and returning -EBUSY. If all (or at least the majority of) drivers using autosuspend end up doing that, *then* we can move that to the core. Thanks, Rafael
On Tue, 28 May 2013, Rafael J. Wysocki wrote: > On Monday, May 13, 2013 01:50:18 PM Rafael J. Wysocki wrote: > > On Monday, May 13, 2013 02:05:27 PM Mika Westerberg wrote: > > > If the device is using autosuspend we should honor that and call > > > pm_runtime_autosuspend() instead of pm_runtime_suspend(). Failing to do so > > > causes the device to be suspended immediately even though it expects to be > > > suspended only when the autosuspend delay is expired. > > > > > > Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com> > > > --- > > > drivers/base/power/generic_ops.c | 5 ++++- > > > 1 file changed, 4 insertions(+), 1 deletion(-) > > > > > > diff --git a/drivers/base/power/generic_ops.c b/drivers/base/power/generic_ops.c > > > index bfd898b..19786ca 100644 > > > --- a/drivers/base/power/generic_ops.c > > > +++ b/drivers/base/power/generic_ops.c > > > @@ -29,7 +29,10 @@ int pm_generic_runtime_idle(struct device *dev) > > > return ret; > > > } > > > > > > - pm_runtime_suspend(dev); > > > + if (dev->power.use_autosuspend) > > > + pm_runtime_autosuspend(dev); > > > + else > > > + pm_runtime_suspend(dev); > > > return 0; > > > > First of all, this is racy (power.use_autosuspend shoud be accessed under > > power.lock). > > > > Second, this is not the only place we'd need to make this change (the analogous > > function for PCI is one example, but there may be others). > > > > Finally, I'm not sure how to address this problem in general. It may be better > > to simply modify rpm_idle() and remove pm_generic_runtime_idle() etc. entirely. > > > > I'll have a look at that, thanks for pointing out the problem. > > I'm not sure if the core is the right place to address this, because it's > not entirely clear if all drivers using autosuspend will have the same policy > with respect to pm_runtime_idle() (i.e. to avoid suspending immediately if > the suspend delay timer is active). > > In my opinion it'd be better to address that in the driver by adding a > .runtime_idle() callback executing pm_runtime_autosuspend(dev) and returning > -EBUSY. Remember that the return value from the runtime_idle callback is ignored. Are you suggesting that the PM core should start paying attention to it? Alan Stern -- To unsubscribe from this list: send the line "unsubscribe linux-pm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Tuesday, May 28, 2013 10:13:35 AM Alan Stern wrote: > On Tue, 28 May 2013, Rafael J. Wysocki wrote: > > > On Monday, May 13, 2013 01:50:18 PM Rafael J. Wysocki wrote: > > > On Monday, May 13, 2013 02:05:27 PM Mika Westerberg wrote: > > > > If the device is using autosuspend we should honor that and call > > > > pm_runtime_autosuspend() instead of pm_runtime_suspend(). Failing to do so > > > > causes the device to be suspended immediately even though it expects to be > > > > suspended only when the autosuspend delay is expired. > > > > > > > > Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com> > > > > --- > > > > drivers/base/power/generic_ops.c | 5 ++++- > > > > 1 file changed, 4 insertions(+), 1 deletion(-) > > > > > > > > diff --git a/drivers/base/power/generic_ops.c b/drivers/base/power/generic_ops.c > > > > index bfd898b..19786ca 100644 > > > > --- a/drivers/base/power/generic_ops.c > > > > +++ b/drivers/base/power/generic_ops.c > > > > @@ -29,7 +29,10 @@ int pm_generic_runtime_idle(struct device *dev) > > > > return ret; > > > > } > > > > > > > > - pm_runtime_suspend(dev); > > > > + if (dev->power.use_autosuspend) > > > > + pm_runtime_autosuspend(dev); > > > > + else > > > > + pm_runtime_suspend(dev); > > > > return 0; > > > > > > First of all, this is racy (power.use_autosuspend shoud be accessed under > > > power.lock). > > > > > > Second, this is not the only place we'd need to make this change (the analogous > > > function for PCI is one example, but there may be others). > > > > > > Finally, I'm not sure how to address this problem in general. It may be better > > > to simply modify rpm_idle() and remove pm_generic_runtime_idle() etc. entirely. > > > > > > I'll have a look at that, thanks for pointing out the problem. > > > > I'm not sure if the core is the right place to address this, because it's > > not entirely clear if all drivers using autosuspend will have the same policy > > with respect to pm_runtime_idle() (i.e. to avoid suspending immediately if > > the suspend delay timer is active). > > > > In my opinion it'd be better to address that in the driver by adding a > > .runtime_idle() callback executing pm_runtime_autosuspend(dev) and returning > > -EBUSY. > > Remember that the return value from the runtime_idle callback is ignored. It is ignored by the core, but some subsystems (those using pm_generic_runtime_idle() in particular) take it into account. > Are you suggesting that the PM core should start paying attention to it? In fact, I was pondering posting a patch making that change. :-) Perhaps I'll just post it for discussion later today ... Thanks, Rafael
diff --git a/drivers/base/power/generic_ops.c b/drivers/base/power/generic_ops.c index bfd898b..19786ca 100644 --- a/drivers/base/power/generic_ops.c +++ b/drivers/base/power/generic_ops.c @@ -29,7 +29,10 @@ int pm_generic_runtime_idle(struct device *dev) return ret; } - pm_runtime_suspend(dev); + if (dev->power.use_autosuspend) + pm_runtime_autosuspend(dev); + else + pm_runtime_suspend(dev); return 0; } EXPORT_SYMBOL_GPL(pm_generic_runtime_idle);
If the device is using autosuspend we should honor that and call pm_runtime_autosuspend() instead of pm_runtime_suspend(). Failing to do so causes the device to be suspended immediately even though it expects to be suspended only when the autosuspend delay is expired. Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com> --- drivers/base/power/generic_ops.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)