drm/probe-helper: don't lose hotplug event

[firefly-linux-kernel-4.4.55.git] / drivers / gpu / drm / drm_probe_helper.c

diff --git a/drivers/gpu/drm/drm_probe_helper.c b/drivers/gpu/drm/drm_probe_helper.c
index 2fbdcca7ca9a7eaa53df5685d76e52443ad9ea89..33bf550a1d3f54b4466fd0584ac7378205cee0c8 100644 (file)
--- a/drivers/gpu/drm/drm_probe_helper.c
+++ b/drivers/gpu/drm/drm_probe_helper.c
@@ -103,6 +103,7 @@ static int drm_helper_probe_single_connector_modes_merge_bits(struct drm_connect
        int count = 0;
        int mode_flags = 0;
        bool verbose_prune = true;
+       enum drm_connector_status old_status;
 
        WARN_ON(!mutex_is_locked(&dev->mode_config.mutex));
 
@@ -121,7 +122,33 @@ 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);
+
+                       /*
+                        * 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);
+               }
        }
 
        /* Re-enable polling in case the global poll config changed. */
@@ -274,10 +301,14 @@ static void output_poll_execute(struct work_struct *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;
+       bool repoll = false, changed;
+
+       /* Pick up any changes detected by the probe functions. */
+       changed = dev->mode_config.delayed_event;
+       dev->mode_config.delayed_event = false;
 
        if (!drm_kms_helper_poll)
-               return;
+               goto out;
 
        mutex_lock(&dev->mode_config.mutex);
        list_for_each_entry(connector, &dev->mode_config.connector_list, head) {
@@ -319,6 +350,7 @@ static void output_poll_execute(struct work_struct *work)
 
        mutex_unlock(&dev->mode_config.mutex);
 
+out:
        if (changed)
                drm_kms_helper_hotplug_event(dev);