[PATCH 2/3] drm: Add an HPD poll helper to reschedule the poll work

[PATCH 2/3] drm: Add an HPD poll helper to reschedule the poll work

[Imre Deak]

Add a helper to reschedule drm_mode_config::output_poll_work after
polling has been enabled for a connector (and needing a reschedule,
since previously polling was disabled for all connectors and hence
output_poll_work was not running).

This is needed by the next patch fixing HPD polling on i915.

Cc: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Cc: dri-devel@lists.freedesktop.org
Signed-off-by: Imre Deak <imre.deak@intel.com>
---
 drivers/gpu/drm/drm_probe_helper.c | 68 ++++++++++++++++++++----------
 include/drm/drm_probe_helper.h     |  1 +
 2 files changed, 47 insertions(+), 22 deletions(-)

diff --git a/drivers/gpu/drm/drm_probe_helper.c b/drivers/gpu/drm/drm_probe_helper.c
index 2fb9bf901a2cc..3f479483d7d80 100644
--- a/drivers/gpu/drm/drm_probe_helper.c
+++ b/drivers/gpu/drm/drm_probe_helper.c
@@ -262,6 +262,26 @@ static bool drm_kms_helper_enable_hpd(struct drm_device *dev)
 }
 
 #define DRM_OUTPUT_POLL_PERIOD (10*HZ)
+static void reschedule_output_poll_work(struct drm_device *dev)
+{
+	unsigned long delay = DRM_OUTPUT_POLL_PERIOD;
+
+	if (dev->mode_config.delayed_event)
+		/*
+		 * FIXME:
+		 *
+		 * Use short (1s) delay to handle the initial delayed event.
+		 * This delay should not be needed, but Optimus/nouveau will
+		 * fail in a mysterious way if the delayed event is handled as
+		 * soon as possible like it is done in
+		 * drm_helper_probe_single_connector_modes() in case the poll
+		 * was enabled before.
+		 */
+		delay = HZ;
+
+	schedule_delayed_work(&dev->mode_config.output_poll_work, delay);
+}
+
 /**
  * drm_kms_helper_poll_enable - re-enable output polling.
  * @dev: drm_device
@@ -279,37 +299,41 @@ static bool drm_kms_helper_enable_hpd(struct drm_device *dev)
  */
 void drm_kms_helper_poll_enable(struct drm_device *dev)
 {
-	bool poll = false;
-	unsigned long delay = DRM_OUTPUT_POLL_PERIOD;
-
 	if (!dev->mode_config.poll_enabled || !drm_kms_helper_poll ||
 	    dev->mode_config.poll_running)
 		return;
 
-	poll = drm_kms_helper_enable_hpd(dev);
-
-	if (dev->mode_config.delayed_event) {
-		/*
-		 * FIXME:
-		 *
-		 * Use short (1s) delay to handle the initial delayed event.
-		 * This delay should not be needed, but Optimus/nouveau will
-		 * fail in a mysterious way if the delayed event is handled as
-		 * soon as possible like it is done in
-		 * drm_helper_probe_single_connector_modes() in case the poll
-		 * was enabled before.
-		 */
-		poll = true;
-		delay = HZ;
-	}
-
-	if (poll)
-		schedule_delayed_work(&dev->mode_config.output_poll_work, delay);
+	if (drm_kms_helper_enable_hpd(dev) ||
+	    dev->mode_config.delayed_event)
+		reschedule_output_poll_work(dev);
 
 	dev->mode_config.poll_running = true;
 }
 EXPORT_SYMBOL(drm_kms_helper_poll_enable);
 
+/**
+ * drm_kms_helper_poll_reschedule - reschedule the output polling work
+ * @dev: drm_device
+ *
+ * This function reschedules the output polling work, after polling for a
+ * connector has been enabled.
+ *
+ * Drivers must call this helper after enabling polling for a connector by
+ * setting %DRM_CONNECTOR_POLL_CONNECT / %DRM_CONNECTOR_POLL_DISCONNECT flags
+ * in drm_connector::polled. Note that after disabling polling by clearing these
+ * flags for a connector will stop the output polling work automatically if
+ * the polling is disabled for all other connectors as well.
+ *
+ * The function can be called only after polling has been enabled by calling
+ * drm_kms_helper_poll_init() / drm_kms_helper_poll_enable().
+ */
+void drm_kms_helper_poll_reschedule(struct drm_device *dev)
+{
+	if (dev->mode_config.poll_running)
+		reschedule_output_poll_work(dev);
+}
+EXPORT_SYMBOL(drm_kms_helper_poll_reschedule);
+
 static enum drm_connector_status
 drm_helper_probe_detect_ctx(struct drm_connector *connector, bool force)
 {
diff --git a/include/drm/drm_probe_helper.h b/include/drm/drm_probe_helper.h
index 4977e0ab72dbb..fad3c4003b2b5 100644
--- a/include/drm/drm_probe_helper.h
+++ b/include/drm/drm_probe_helper.h
@@ -25,6 +25,7 @@ void drm_kms_helper_connector_hotplug_event(struct drm_connector *connector);
 
 void drm_kms_helper_poll_disable(struct drm_device *dev);
 void drm_kms_helper_poll_enable(struct drm_device *dev);
+void drm_kms_helper_poll_reschedule(struct drm_device *dev);
 bool drm_kms_helper_is_poll_worker(void);
 
 enum drm_mode_status drm_crtc_helper_mode_valid_fixed(struct drm_crtc *crtc,
-- 
2.37.2

[PATCH 3/3] drm/i915: Fix HPD polling, reenabling the output poll work as needed

[Imre Deak]

After the commit in the Fixes: line below, HPD polling stopped working
on i915, since after that change calling drm_kms_helper_poll_enable()
doesn't restart drm_mode_config::output_poll_work if the work was
stopped (no connectors needing polling) and enabling polling for a
connector (during runtime suspend or detecting an HPD IRQ storm).

After the above change calling drm_kms_helper_poll_enable() is a nop
after it's been called already and polling for some connectors was
disabled/re-enabled.

Fix this by calling drm_kms_helper_poll_reschedule() added in the
previous patch instead, which reschedules the work whenever expected.

Fixes: d33a54e3991d ("drm/probe_helper: sort out poll_running vs poll_enabled")
Cc: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Cc: dri-devel@lists.freedesktop.org
Signed-off-by: Imre Deak <imre.deak@intel.com>
---
 drivers/gpu/drm/i915/display/intel_hotplug.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_hotplug.c b/drivers/gpu/drm/i915/display/intel_hotplug.c
index 3780629bff95c..cc49040445f39 100644
--- a/drivers/gpu/drm/i915/display/intel_hotplug.c
+++ b/drivers/gpu/drm/i915/display/intel_hotplug.c
@@ -212,7 +212,7 @@ intel_hpd_irq_storm_switch_to_polling(struct drm_i915_private *dev_priv)
 
 	/* Enable polling and queue hotplug re-enabling. */
 	if (hpd_disabled) {
-		drm_kms_helper_poll_enable(&dev_priv->drm);
+		drm_kms_helper_poll_reschedule(&dev_priv->drm);
 		mod_delayed_work(dev_priv->unordered_wq,
 				 &dev_priv->display.hotplug.reenable_work,
 				 msecs_to_jiffies(HPD_STORM_REENABLE_DELAY));
@@ -676,7 +676,7 @@ static void i915_hpd_poll_init_work(struct work_struct *work)
 	drm_connector_list_iter_end(&conn_iter);
 
 	if (enabled)
-		drm_kms_helper_poll_enable(&dev_priv->drm);
+		drm_kms_helper_poll_reschedule(&dev_priv->drm);
 
 	mutex_unlock(&dev_priv->drm.mode_config.mutex);
 
-- 
2.37.2