| Message ID | 2060154.irdbgypaU6@kreacher (mailing list archive) |
|---|---|
| State | Superseded, archived |
| Headers | show |
| Series | PM: runtime: Update device status before letting suppliers suspend (another take) | expand |
On Thu, 18 Mar 2021 at 19:15, Rafael J. Wysocki <rjw@rjwysocki.net> wrote: > > From: Rafael J. Wysocki <rafael.j.wysocki@intel.com> > > Because the PM-runtime status of the device is not updated in > __rpm_callback(), attempts to suspend the suppliers of the given > device triggered by the rpm_put_suppliers() call in there may fail. > > To fix this (1) modify __rpm_callback() to avoid attempting to > actually suspend the suppliers, but only decrease their PM-runtime > usage counters and (2) make rpm_suspend() try to suspend the suppliers > after changing the device's PM-runtime status, in analogy with the > handling of the device's parent. > > Link: https://lore.kernel.org/linux-pm/CAPDyKFqm06KDw_p8WXsM4dijDbho4bb6T4k50UqqvR1_COsp8g@mail.gmail.com/ > Fixes: 21d5c57b3726 ("PM / runtime: Use device links") > Reported-by: elaine.zhang <zhangqing@rock-chips.com> > Diagnosed-by: Ulf Hansson <ulf.hansson@linaro.org> > Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Just a minor nitpick, see below. In any case: Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org> > --- > drivers/base/power/runtime.c | 45 +++++++++++++++++++++++++++++++++++++------ > 1 file changed, 39 insertions(+), 6 deletions(-) > > Index: linux-pm/drivers/base/power/runtime.c > =================================================================== > --- linux-pm.orig/drivers/base/power/runtime.c > +++ linux-pm/drivers/base/power/runtime.c > @@ -305,7 +305,7 @@ static int rpm_get_suppliers(struct devi > return 0; > } > > -static void rpm_put_suppliers(struct device *dev) > +static void __rpm_put_suppliers(struct device *dev, bool try_to_suspend) > { > struct device_link *link; > > @@ -313,10 +313,30 @@ static void rpm_put_suppliers(struct dev > device_links_read_lock_held()) { > > while (refcount_dec_not_one(&link->rpm_active)) > - pm_runtime_put(link->supplier); > + pm_runtime_put_noidle(link->supplier); > + > + if (try_to_suspend) > + pm_request_idle(link->supplier); > } > } > > +static void rpm_put_suppliers(struct device *dev) > +{ > + __rpm_put_suppliers(dev, true); > +} > + > +static void rpm_try_to_suspend_suppliers(struct device *dev) Maybe "rpm_suspend_suppliers" is sufficient for the name of the function, but I have no strong opinion. > +{ > + struct device_link *link; > + int idx = device_links_read_lock(); > + > + list_for_each_entry_rcu(link, &dev->links.suppliers, c_node, > + device_links_read_lock_held()) > + pm_request_idle(link->supplier); > + > + device_links_read_unlock(idx); > +} > + [...] Kind regards Uffe
On Fri, Mar 19, 2021 at 2:30 PM Ulf Hansson <ulf.hansson@linaro.org> wrote: > > On Thu, 18 Mar 2021 at 19:15, Rafael J. Wysocki <rjw@rjwysocki.net> wrote: > > > > From: Rafael J. Wysocki <rafael.j.wysocki@intel.com> > > > > Because the PM-runtime status of the device is not updated in > > __rpm_callback(), attempts to suspend the suppliers of the given > > device triggered by the rpm_put_suppliers() call in there may fail. > > > > To fix this (1) modify __rpm_callback() to avoid attempting to > > actually suspend the suppliers, but only decrease their PM-runtime > > usage counters and (2) make rpm_suspend() try to suspend the suppliers > > after changing the device's PM-runtime status, in analogy with the > > handling of the device's parent. > > > > Link: https://lore.kernel.org/linux-pm/CAPDyKFqm06KDw_p8WXsM4dijDbho4bb6T4k50UqqvR1_COsp8g@mail.gmail.com/ > > Fixes: 21d5c57b3726 ("PM / runtime: Use device links") > > Reported-by: elaine.zhang <zhangqing@rock-chips.com> > > Diagnosed-by: Ulf Hansson <ulf.hansson@linaro.org> > > Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> > > Just a minor nitpick, see below. In any case: > > Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org> Thanks! > > > --- > > drivers/base/power/runtime.c | 45 +++++++++++++++++++++++++++++++++++++------ > > 1 file changed, 39 insertions(+), 6 deletions(-) > > > > Index: linux-pm/drivers/base/power/runtime.c > > =================================================================== > > --- linux-pm.orig/drivers/base/power/runtime.c > > +++ linux-pm/drivers/base/power/runtime.c > > @@ -305,7 +305,7 @@ static int rpm_get_suppliers(struct devi > > return 0; > > } > > > > -static void rpm_put_suppliers(struct device *dev) > > +static void __rpm_put_suppliers(struct device *dev, bool try_to_suspend) > > { > > struct device_link *link; > > > > @@ -313,10 +313,30 @@ static void rpm_put_suppliers(struct dev > > device_links_read_lock_held()) { > > > > while (refcount_dec_not_one(&link->rpm_active)) > > - pm_runtime_put(link->supplier); > > + pm_runtime_put_noidle(link->supplier); > > + > > + if (try_to_suspend) > > + pm_request_idle(link->supplier); > > } > > } > > > > +static void rpm_put_suppliers(struct device *dev) > > +{ > > + __rpm_put_suppliers(dev, true); > > +} > > + > > +static void rpm_try_to_suspend_suppliers(struct device *dev) > > Maybe "rpm_suspend_suppliers" is sufficient for the name of the > function, but I have no strong opinion. OK In addition to this, spin_unlock_irq()/spin_lock_irq() need to be used around the call to it in rpm_suspend(), so I'll send a v2. I guess that the R-by still applies, though. :-) > > +{ > > + struct device_link *link; > > + int idx = device_links_read_lock(); > > + > > + list_for_each_entry_rcu(link, &dev->links.suppliers, c_node, > > + device_links_read_lock_held()) > > + pm_request_idle(link->supplier); > > + > > + device_links_read_unlock(idx); > > +} > > +
Index: linux-pm/drivers/base/power/runtime.c =================================================================== --- linux-pm.orig/drivers/base/power/runtime.c +++ linux-pm/drivers/base/power/runtime.c @@ -305,7 +305,7 @@ static int rpm_get_suppliers(struct devi return 0; } -static void rpm_put_suppliers(struct device *dev) +static void __rpm_put_suppliers(struct device *dev, bool try_to_suspend) { struct device_link *link; @@ -313,10 +313,30 @@ static void rpm_put_suppliers(struct dev device_links_read_lock_held()) { while (refcount_dec_not_one(&link->rpm_active)) - pm_runtime_put(link->supplier); + pm_runtime_put_noidle(link->supplier); + + if (try_to_suspend) + pm_request_idle(link->supplier); } } +static void rpm_put_suppliers(struct device *dev) +{ + __rpm_put_suppliers(dev, true); +} + +static void rpm_try_to_suspend_suppliers(struct device *dev) +{ + struct device_link *link; + int idx = device_links_read_lock(); + + list_for_each_entry_rcu(link, &dev->links.suppliers, c_node, + device_links_read_lock_held()) + pm_request_idle(link->supplier); + + device_links_read_unlock(idx); +} + /** * __rpm_callback - Run a given runtime PM callback for a given device. * @cb: Runtime PM callback to run. @@ -344,8 +364,10 @@ static int __rpm_callback(int (*cb)(stru idx = device_links_read_lock(); retval = rpm_get_suppliers(dev); - if (retval) + if (retval) { + rpm_put_suppliers(dev); goto fail; + } device_links_read_unlock(idx); } @@ -368,9 +390,9 @@ static int __rpm_callback(int (*cb)(stru || (dev->power.runtime_status == RPM_RESUMING && retval))) { idx = device_links_read_lock(); - fail: - rpm_put_suppliers(dev); + __rpm_put_suppliers(dev, false); +fail: device_links_read_unlock(idx); } @@ -642,8 +664,11 @@ static int rpm_suspend(struct device *de goto out; } + if (dev->power.irq_safe) + goto out; + /* Maybe the parent is now able to suspend. */ - if (parent && !parent->power.ignore_children && !dev->power.irq_safe) { + if (parent && !parent->power.ignore_children) { spin_unlock(&dev->power.lock); spin_lock(&parent->power.lock); @@ -652,6 +677,14 @@ static int rpm_suspend(struct device *de spin_lock(&dev->power.lock); } + /* Maybe the suppliers are now able to suspend. */ + if (dev->power.links_count > 0) { + spin_unlock(&dev->power.lock); + + rpm_try_to_suspend_suppliers(dev); + + spin_lock(&dev->power.lock); + } out: trace_rpm_return_int_rcuidle(dev, _THIS_IP_, retval);