drm/sysfs: Send out uevent when connector->force changes

To avoid even more code duplication punt this all to the probe worker,
which needs some slight adjustment to also generate a uevent when the
status has changed to due connector->force.

v2: Instead of running the output_poll_work (which is kinda the wrong
thing and a layering violation since it's an internal of the probe
helpers), or calling ->detect (which is again a layering violation
since it's used only by probe helpers) just call the official
->fill_modes function, like a GET_CONNECTOR ioctl call.

v3: Restore the accidentally removed forced-probe for echo "detect" >
force.

Cc: Chris Wilson <chris@chris-wilson.co.uk>
Reported-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1447951610-12622-22-git-send-email-daniel.vetter@ffwll.ch
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/drm_probe_helper.c

@@ -147,6 +147,8 @@ static int drm_helper_probe_single_connector_modes_merge_bits(struct drm_connect
 	list_for_each_entry(mode, &connector->modes, head)
 		mode->status = MODE_UNVERIFIED;
 
+	old_status = connector->status;
+
 	if (connector->force) {
 		if (connector->force == DRM_FORCE_ON ||
 		    connector->force == DRM_FORCE_ON_DIGITAL)
@@ -156,33 +158,31 @@ static int drm_helper_probe_single_connector_modes_merge_bits(struct drm_connect
 		if (connector->funcs->force)
 			connector->funcs->force(connector);
 	} else {
-		old_status = connector->status;
-
 		connector->status = connector->funcs->detect(connector, true);
+	}
+
+	/*
+	 * Normally either the driver's hpd code or the poll loop should
+	 * pick up any changes and fire the hotplug event. But if
+	 * userspace sneaks in a probe, we might miss a change. Hence
+	 * check here, and if anything changed start the hotplug code.
+	 */
+	if (old_status != connector->status) {
+		DRM_DEBUG_KMS("[CONNECTOR:%d:%s] status updated from %d to %d\n",
+			      connector->base.id,
+			      connector->name,
+			      old_status, connector->status);
 
 		/*
-		 * Normally either the driver's hpd code or the poll loop should
-		 * pick up any changes and fire the hotplug event. But if
-		 * userspace sneaks in a probe, we might miss a change. Hence
-		 * check here, and if anything changed start the hotplug code.
+		 * The hotplug event code might call into the fb
+		 * helpers, and so expects that we do not hold any
+		 * locks. Fire up the poll struct instead, it will
+		 * disable itself again.
 		 */
-		if (old_status != connector->status) {
-			DRM_DEBUG_KMS("[CONNECTOR:%d:%s] status updated from %d to %d\n",
-				      connector->base.id,
-				      connector->name,
-				      old_status, connector->status);
-
-			/*
-			 * The hotplug event code might call into the fb
-			 * helpers, and so expects that we do not hold any
-			 * locks. Fire up the poll struct instead, it will
-			 * disable itself again.
-			 */
-			dev->mode_config.delayed_event = true;
-			if (dev->mode_config.poll_enabled)
-				schedule_delayed_work(&dev->mode_config.output_poll_work,
-						      0);
-		}
+		dev->mode_config.delayed_event = true;
+		if (dev->mode_config.poll_enabled)
+			schedule_delayed_work(&dev->mode_config.output_poll_work,
+					      0);
 	}
 
 	/* Re-enable polling in case the global poll config changed. */

drivers/gpu/drm/drm_sysfs.c

@@ -167,47 +167,35 @@ static ssize_t status_store(struct device *device,
 {
 	struct drm_connector *connector = to_drm_connector(device);
 	struct drm_device *dev = connector->dev;
-	enum drm_connector_status old_status;
+	enum drm_connector_force old_force;
 	int ret;
 
 	ret = mutex_lock_interruptible(&dev->mode_config.mutex);
 	if (ret)
 		return ret;
 
-	old_status = connector->status;
+	old_force = connector->force;
 
-	if (sysfs_streq(buf, "detect")) {
+	if (sysfs_streq(buf, "detect"))
 		connector->force = 0;
-		connector->status = connector->funcs->detect(connector, true);
-	} else if (sysfs_streq(buf, "on")) {
+	else if (sysfs_streq(buf, "on"))
 		connector->force = DRM_FORCE_ON;
-	} else if (sysfs_streq(buf, "on-digital")) {
+	else if (sysfs_streq(buf, "on-digital"))
 		connector->force = DRM_FORCE_ON_DIGITAL;
-	} else if (sysfs_streq(buf, "off")) {
+	else if (sysfs_streq(buf, "off"))
 		connector->force = DRM_FORCE_OFF;
-	} else
+	else
 		ret = -EINVAL;
 
-	if (ret == 0 && connector->force) {
-		if (connector->force == DRM_FORCE_ON ||
-		    connector->force == DRM_FORCE_ON_DIGITAL)
-			connector->status = connector_status_connected;
-		else
-			connector->status = connector_status_disconnected;
-		if (connector->funcs->force)
-			connector->funcs->force(connector);
-	}
-
-	if (old_status != connector->status) {
-		DRM_DEBUG_KMS("[CONNECTOR:%d:%s] status updated from %d to %d\n",
+	if (old_force != connector->force || !connector->force) {
+		DRM_DEBUG_KMS("[CONNECTOR:%d:%s] force updated from %d to %d or reprobing\n",
 			      connector->base.id,
 			      connector->name,
-			      old_status, connector->status);
+			      old_force, connector->force);
 
-		dev->mode_config.delayed_event = true;
-		if (dev->mode_config.poll_enabled)
-			schedule_delayed_work(&dev->mode_config.output_poll_work,
-					      0);
+		connector->funcs->fill_modes(connector,
+					     dev->mode_config.max_width,
+					     dev->mode_config.max_height);
 	}
 
 	mutex_unlock(&dev->mode_config.mutex);