[PATCH] drm: Never change the connector status to unknown whilst polling

[Chris Wilson]

When polling for a hotplug event, if the connector detect probe returns
unknown, reuse the current status and do not trigger a hotplug event.

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
---
 drivers/gpu/drm/drm_crtc.c        |    1 +
 drivers/gpu/drm/drm_crtc_helper.c |   11 +++++++----
 2 files changed, 8 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
index 2baa670..f6678f6 100644
--- a/drivers/gpu/drm/drm_crtc.c
+++ b/drivers/gpu/drm/drm_crtc.c
@@ -459,6 +459,7 @@ void drm_connector_init(struct drm_device *dev,
 	INIT_LIST_HEAD(&connector->probed_modes);
 	INIT_LIST_HEAD(&connector->modes);
 	connector->edid_blob_ptr = NULL;
+	connector->status = connector_status_unknown;
 
 	list_add_tail(&connector->head, &dev->mode_config.connector_list);
 	dev->mode_config.num_connector++;
diff --git a/drivers/gpu/drm/drm_crtc_helper.c b/drivers/gpu/drm/drm_crtc_helper.c
index 952b3d4..b3afb38 100644
--- a/drivers/gpu/drm/drm_crtc_helper.c
+++ b/drivers/gpu/drm/drm_crtc_helper.c
@@ -862,7 +862,6 @@ static void output_poll_execute(struct work_struct *work)
 	struct delayed_work *delayed_work = to_delayed_work(work);
 	struct drm_device *dev = container_of(delayed_work, struct drm_device, mode_config.output_poll_work);
 	struct drm_connector *connector;
-	enum drm_connector_status old_status;
 	bool repoll = false, changed = false;
 
 	if (!drm_kms_helper_poll)
@@ -870,6 +869,7 @@ static void output_poll_execute(struct work_struct *work)
 
 	mutex_lock(&dev->mode_config.mutex);
 	list_for_each_entry(connector, &dev->mode_config.connector_list, head) {
+		enum drm_connector_status old_status, new_status;
 
 		/* if this is HPD or polled don't check it -
 		   TV out for instance */
@@ -883,15 +883,18 @@ static void output_poll_execute(struct work_struct *work)
 		/* if we are connected and don't want to poll for disconnect
 		   skip it */
 		if (old_status == connector_status_connected &&
-		    !(connector->polled & DRM_CONNECTOR_POLL_DISCONNECT) &&
-		    !(connector->polled & DRM_CONNECTOR_POLL_HPD))
+		    (connector->polled & (DRM_CONNECTOR_POLL_DISCONNECT | DRM_CONNECTOR_POLL_HPD)) == 0)
 			continue;
 
-		connector->status = connector->funcs->detect(connector, false);
+		new_status = connector->funcs->detect(connector, false);
+		if (new_status != connector_status_unknown)
+			connector->status = new_status;
+
 		DRM_DEBUG_KMS("[CONNECTOR:%d:%s] status updated from %d to %d\n",
 			      connector->base.id,
 			      drm_get_connector_name(connector),
 			      old_status, connector->status);
+
 		if (old_status != connector->status)
 			changed = true;
 	}
-- 
1.7.2.3