Hi,
Note this v4 is send from my gmail in an attempt to keep the
X-Mailer: git-send-email header which the test-infra wants, but
that seems to have failed.
I've also just send another copy through my isp-s mail server,
but I've not received a copy of that copy myself ? If anyone
else has a second copy of this series can you please check if
the git-send-email header is there ?
If not can someone resend this series so that it can go through
the test infra ?
Regards,
Hans
On 20-08-17 14:51, 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@xxxxxxxxxxx>
Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx>
Reviewed-by: Imre Deak <imre.deak@xxxxxxxxx>
---
Changes in v2:
-Rebase on current (July 6th 2017) drm-next
Changes in v3:
-Reword comment explaining why disabling the wakeref asserts is
ok and necessary
-Add Imre's Reviewed-by
---
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 1d7b879cc68c..2d3aad319229 100644
--- a/drivers/gpu/drm/i915/intel_uncore.c
+++ b/drivers/gpu/drm/i915/intel_uncore.c
@@ -1171,8 +1171,15 @@ 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);
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