drm/i915: Fix false-positive assert_rpm_wakelock_held in i915_pmic_bus_access_notifier v2
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> Link: https://patchwork.freedesktop.org/patch/msgid/20171110150301.9601-2-hdegoede@redhat.com
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