| Message ID | 20170519132704.25527-1-hdegoede@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Hi, On 19-05-17 15:27, Hans de Goede wrote: > assert_rpm_wakelock_held is triggered from i915_pmic_bus_access_notifier > even though it gets unregistered on (runtime) suspend, this is caused > by a race happening under the following circumstances: > > intel_runtime_pm_put does: > > atomic_dec(&dev_priv->pm.wakeref_count); > > pm_runtime_mark_last_busy(kdev); > pm_runtime_put_autosuspend(kdev); > > And pm_runtime_put_autosuspend calls intel_runtime_suspend from > a workqueue, so there is ample of time between the atomic_dec() and > intel_runtime_suspend() unregistering the notifier. If the notifier > gets called in this windowd assert_rpm_wakelock_held falsely triggers > (at this point we're not runtime-suspended yet). > > This commit adds disable_rpm_wakeref_asserts and > enable_rpm_wakeref_asserts calls around the > intel_uncore_forcewake_get(FORCEWAKE_ALL) call in > i915_pmic_bus_access_notifier fixing the false-positive WARN_ON. > > Reported-by: FKr <bugs-freedesktop@ubermail.me> > Signed-off-by: Hans de Goede <hdegoede@redhat.com> Ping, what is the status of this series? I've been running this series on several Bay and Cherry Trail devices since I posted this without issues. As this fixes a couple of corner case wrt the pmic bus access sharing merged for 4.12, it would be nice to get these queued up and of possible added to a 4.12-rc#. The only patch which changes code / functionality which was present in 4.11 is the 3th patch, which I added because Ville requested the change. The other 3 can be queued up for 4.12 without the 3th patch. Regards, Hans > --- > drivers/gpu/drm/i915/intel_uncore.c | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/drivers/gpu/drm/i915/intel_uncore.c b/drivers/gpu/drm/i915/intel_uncore.c > index 6d1ea26b2493..dc5e4f3e5a43 100644 > --- a/drivers/gpu/drm/i915/intel_uncore.c > +++ b/drivers/gpu/drm/i915/intel_uncore.c > @@ -1286,8 +1286,15 @@ static int i915_pmic_bus_access_notifier(struct notifier_block *nb, > * bus, which will be busy after this notification, leading to: > * "render: timed out waiting for forcewake ack request." > * errors. > + * > + * This notifier may get called between intel_runtime_pm_put() > + * doing atomic_dec(wakeref_count) and intel_runtime_resume() > + * unregistering this notifier, which leads to false-positive > + * assert_rpm_wakelock_held() triggering. > */ > + disable_rpm_wakeref_asserts(dev_priv); > intel_uncore_forcewake_get(dev_priv, FORCEWAKE_ALL); > + enable_rpm_wakeref_asserts(dev_priv); > break; > case MBI_PMIC_BUS_ACCESS_END: > intel_uncore_forcewake_put(dev_priv, FORCEWAKE_ALL); >
diff --git a/drivers/gpu/drm/i915/intel_uncore.c b/drivers/gpu/drm/i915/intel_uncore.c index 6d1ea26b2493..dc5e4f3e5a43 100644 --- a/drivers/gpu/drm/i915/intel_uncore.c +++ b/drivers/gpu/drm/i915/intel_uncore.c @@ -1286,8 +1286,15 @@ static int i915_pmic_bus_access_notifier(struct notifier_block *nb, * bus, which will be busy after this notification, leading to: * "render: timed out waiting for forcewake ack request." * errors. + * + * This notifier may get called between intel_runtime_pm_put() + * doing atomic_dec(wakeref_count) and intel_runtime_resume() + * unregistering this notifier, which leads to false-positive + * assert_rpm_wakelock_held() triggering. */ + disable_rpm_wakeref_asserts(dev_priv); intel_uncore_forcewake_get(dev_priv, FORCEWAKE_ALL); + enable_rpm_wakeref_asserts(dev_priv); break; case MBI_PMIC_BUS_ACCESS_END: intel_uncore_forcewake_put(dev_priv, FORCEWAKE_ALL);
assert_rpm_wakelock_held is triggered from i915_pmic_bus_access_notifier even though it gets unregistered on (runtime) suspend, this is caused by a race happening under the following circumstances: intel_runtime_pm_put does: atomic_dec(&dev_priv->pm.wakeref_count); pm_runtime_mark_last_busy(kdev); pm_runtime_put_autosuspend(kdev); And pm_runtime_put_autosuspend calls intel_runtime_suspend from a workqueue, so there is ample of time between the atomic_dec() and intel_runtime_suspend() unregistering the notifier. If the notifier gets called in this windowd assert_rpm_wakelock_held falsely triggers (at this point we're not runtime-suspended yet). This commit adds disable_rpm_wakeref_asserts and enable_rpm_wakeref_asserts calls around the intel_uncore_forcewake_get(FORCEWAKE_ALL) call in i915_pmic_bus_access_notifier fixing the false-positive WARN_ON. Reported-by: FKr <bugs-freedesktop@ubermail.me> Signed-off-by: Hans de Goede <hdegoede@redhat.com> --- drivers/gpu/drm/i915/intel_uncore.c | 7 +++++++ 1 file changed, 7 insertions(+)