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.

Changes in v2: -Reword comment explaining why disabling the wakeref asserts is ok and necessary

Cc: stable@vger.kernel.org Reported-by: FKr bugs-freedesktop@ubermail.me Reviewed-by: Imre Deak imre.deak@intel.com Signed-off-by: Hans de Goede hdegoede@redhat.com --- 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 211acee7c31d..dbc5cc309cbc 100644 --- a/drivers/gpu/drm/i915/intel_uncore.c +++ b/drivers/gpu/drm/i915/intel_uncore.c @@ -1364,8 +1364,15 @@ 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. + * + * The notifier is unregistered during intel_runtime_suspend(), + * so it's ok to access the HW here without holding a RPM + * wake reference -> disable wakeref asserts for the time of + * the access. */ + 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);