If an HPD IRQ storm is detected on a connector during driver loading or
system suspend/resume - disabling the IRQ and switching to polling - the
polling may get disabled too early - before the intended 2 minute
HPD_STORM_REENABLE_DELAY - with the HPD IRQ staying disabled for this
duration. One such sequence is:
Thread#1 Thread#2
intel_display_driver_probe()->
intel_hpd_init()->
(HPD IRQ gets enabled)
. intel_hpd_irq_handler()->
. intel_hpd_irq_storm_detect()
. intel_hpd_irq_setup()->
. (HPD IRQ gets disabled)
. queue_delayed_work(hotplug.hotplug_work)
. ...
. i915_hotplug_work_func()->
. intel_hpd_irq_storm_switch_to_polling()->
. (polling enabled)
.
intel_hpd_poll_disable()->
queue_work(hotplug.poll_init_work)
...
i915_hpd_poll_init_work()->
(polling gets disabled,
HPD IRQ is still disabled)
...
(Connector is neither polled or
detected via HPD IRQs for 2 minutes)
intel_hpd_irq_storm_reenable_work()->
(HPD IRQ gets enabled)
To avoid the above 2 minute state without either polling or enabled HPD
IRQ, leave the connector's polling mode unchanged in
i915_hpd_poll_init_work() if its HPD IRQ got disabled after an IRQ storm
indicated by the connector's HPD_DISABLED pin state.
Signed-off-by: Imre Deak <imre.deak@xxxxxxxxx>
---
drivers/gpu/drm/i915/display/intel_hotplug.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/drivers/gpu/drm/i915/display/intel_hotplug.c b/drivers/gpu/drm/i915/display/intel_hotplug.c
index 0c0700c6ec66d..74513c3d3690b 100644
--- a/drivers/gpu/drm/i915/display/intel_hotplug.c
+++ b/drivers/gpu/drm/i915/display/intel_hotplug.c
@@ -710,6 +710,8 @@ static void i915_hpd_poll_init_work(struct work_struct *work)
cancel_work(&dev_priv->display.hotplug.poll_init_work);
}
+ spin_lock_irq(&dev_priv->irq_lock);
+
drm_connector_list_iter_begin(&dev_priv->drm, &conn_iter);
for_each_intel_connector_iter(connector, &conn_iter) {
enum hpd_pin pin;
@@ -718,6 +720,9 @@ static void i915_hpd_poll_init_work(struct work_struct *work)
if (pin == HPD_NONE)
continue;
+ if (dev_priv->display.hotplug.stats[pin].state == HPD_DISABLED)
+ continue;
+
connector->base.polled = connector->polled;
if (enabled && connector->base.polled == DRM_CONNECTOR_POLL_HPD)
@@ -726,6 +731,8 @@ static void i915_hpd_poll_init_work(struct work_struct *work)
}
drm_connector_list_iter_end(&conn_iter);
+ spin_unlock_irq(&dev_priv->irq_lock);
+
if (enabled)
drm_kms_helper_poll_reschedule(&dev_priv->drm);
--
2.39.2
