Merge tag 'topic/drm-misc-2016-05-08' of git://anongit.freedesktop.org/drm-intel into drm-next

Refcounting is hard, so here's a quick pull request with the one-liner to
fix up i915. Otherwise just a few other small things I picked up. Plus the
regression fix from Marten for rmfb behaviour that lingered around forever
since no testers. Feel free to cherry-pick that over to drm-fixes, but
given that there's not many who seemed to have cared, meh.

* tag 'topic/drm-misc-2016-05-08' of git://anongit.freedesktop.org/drm-intel:
  drm/i915: Correctly refcount connectors in hw state readou
  drm/panel: Flesh out kerneldoc
  drm: Add gpu.tmpl docbook to MAINTAINERS entry
  drm/core: Do not preserve framebuffer on rmfb, v4.
  drm: Fix up markup fumble
  drm/fb_helper: Fix a few typos

8 files changed, 195 insertions, 14 deletions

diff --git a/Documentation/DocBook/gpu.tmpl b/Documentation/DocBook/gpu.tmpl
index 56386d3a1b2e..9dd48f7490df 100644
--- a/Documentation/DocBook/gpu.tmpl
+++ b/Documentation/DocBook/gpu.tmpl
@@ -1671,17 +1671,23 @@ void intel_crt_init(struct drm_device *dev)
 !Pdrivers/gpu/drm/drm_crtc.c Tile group
     </sect2>
     <sect2>
-	<title>Bridges</title>
+      <title>Bridges</title>
       <sect3>
-	 <title>Overview</title>
+        <title>Overview</title>
 !Pdrivers/gpu/drm/drm_bridge.c overview
       </sect3>
       <sect3>
-	 <title>Default bridge callback sequence</title>
+        <title>Default bridge callback sequence</title>
 !Pdrivers/gpu/drm/drm_bridge.c bridge callbacks
       </sect3>
 !Edrivers/gpu/drm/drm_bridge.c
     </sect2>
+    <sect2>
+      <title>Panel Helper Reference</title>
+!Iinclude/drm/drm_panel.h
+!Edrivers/gpu/drm/drm_panel.c
+!Pdrivers/gpu/drm/drm_panel.c drm panel
+    </sect2>
   </sect1>
 
   <!-- Internals: kms properties -->
diff --git a/MAINTAINERS b/MAINTAINERS
index e6ee4ecf34b0..33181d862e5a 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -3765,6 +3765,7 @@ T:	git git://people.freedesktop.org/~airlied/linux
 S:	Maintained
 F:	drivers/gpu/drm/
 F:	drivers/gpu/vga/
+F:	Documentation/DocBook/gpu.*
 F:	include/drm/
 F:	include/uapi/drm/
 
diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
index a9c0a4348322..70f9c682d144 100644
--- a/drivers/gpu/drm/drm_crtc.c
+++ b/drivers/gpu/drm/drm_crtc.c
@@ -3462,6 +3462,24 @@ int drm_mode_addfb2(struct drm_device *dev,
 	return 0;
 }
 
+struct drm_mode_rmfb_work {
+	struct work_struct work;
+	struct list_head fbs;
+};
+
+static void drm_mode_rmfb_work_fn(struct work_struct *w)
+{
+	struct drm_mode_rmfb_work *arg = container_of(w, typeof(*arg), work);
+
+	while (!list_empty(&arg->fbs)) {
+		struct drm_framebuffer *fb =
+			list_first_entry(&arg->fbs, typeof(*fb), filp_head);
+
+		list_del_init(&fb->filp_head);
+		drm_framebuffer_remove(fb);
+	}
+}
+
 /**
  * drm_mode_rmfb - remove an FB from the configuration
  * @dev: drm device for the ioctl
@@ -3502,12 +3520,29 @@ int drm_mode_rmfb(struct drm_device *dev,
 	list_del_init(&fb->filp_head);
 	mutex_unlock(&file_priv->fbs_lock);
 
-	/* we now own the reference that was stored in the fbs list */
-	drm_framebuffer_unreference(fb);
-
 	/* drop the reference we picked up in framebuffer lookup */
 	drm_framebuffer_unreference(fb);
 
+	/*
+	 * we now own the reference that was stored in the fbs list
+	 *
+	 * drm_framebuffer_remove may fail with -EINTR on pending signals,
+	 * so run this in a separate stack as there's no way to correctly
+	 * handle this after the fb is already removed from the lookup table.
+	 */
+	if (drm_framebuffer_read_refcount(fb) > 1) {
+		struct drm_mode_rmfb_work arg;
+
+		INIT_WORK_ONSTACK(&arg.work, drm_mode_rmfb_work_fn);
+		INIT_LIST_HEAD(&arg.fbs);
+		list_add_tail(&fb->filp_head, &arg.fbs);
+
+		schedule_work(&arg.work);
+		flush_work(&arg.work);
+		destroy_work_on_stack(&arg.work);
+	} else
+		drm_framebuffer_unreference(fb);
+
 	return 0;
 
 fail_unref:
@@ -3657,7 +3692,6 @@ out_err1:
 	return ret;
 }
 
-
 /**
  * drm_fb_release - remove and free the FBs on this file
  * @priv: drm file for the ioctl
@@ -3672,6 +3706,9 @@ out_err1:
 void drm_fb_release(struct drm_file *priv)
 {
 	struct drm_framebuffer *fb, *tfb;
+	struct drm_mode_rmfb_work arg;
+
+	INIT_LIST_HEAD(&arg.fbs);
 
 	/*
 	 * When the file gets released that means no one else can access the fb
@@ -3684,10 +3721,22 @@ void drm_fb_release(struct drm_file *priv)
 	 * at it any more.
 	 */
 	list_for_each_entry_safe(fb, tfb, &priv->fbs, filp_head) {
-		list_del_init(&fb->filp_head);
+		if (drm_framebuffer_read_refcount(fb) > 1) {
+			list_move_tail(&fb->filp_head, &arg.fbs);
+		} else {
+			list_del_init(&fb->filp_head);
 
-		/* This drops the fpriv->fbs reference. */
-		drm_framebuffer_unreference(fb);
+			/* This drops the fpriv->fbs reference. */
+			drm_framebuffer_unreference(fb);
+		}
+	}
+
+	if (!list_empty(&arg.fbs)) {
+		INIT_WORK_ONSTACK(&arg.work, drm_mode_rmfb_work_fn);
+
+		schedule_work(&arg.work);
+		flush_work(&arg.work);
+		destroy_work_on_stack(&arg.work);
 	}
 }
 
diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c
index 0bb3d4bee24c..385284bc773c 100644
--- a/drivers/gpu/drm/drm_fb_helper.c
+++ b/drivers/gpu/drm/drm_fb_helper.c
@@ -2177,8 +2177,8 @@ out:
  * cmdline option.
  *
  * The other option is to just disable fbdev emulation since very likely the
- * first modest from userspace will crash in the same way, and is even easier to
- * debug. This can be done by setting the drm_kms_helper.fbdev_emulation=0
+ * first modeset from userspace will crash in the same way, and is even easier
+ * to debug. This can be done by setting the drm_kms_helper.fbdev_emulation=0
  * kernel cmdline option.
  *
  * RETURNS:
@@ -2223,7 +2223,7 @@ EXPORT_SYMBOL(drm_fb_helper_initial_config);
  * hotplug interrupt).
  *
  * Note that drivers may call this even before calling
- * drm_fb_helper_initial_config but only aftert drm_fb_helper_init. This allows
+ * drm_fb_helper_initial_config but only after drm_fb_helper_init. This allows
  * for a race-free fbcon setup and will make sure that the fbdev emulation will
  * not miss any hotplug events.
  *
diff --git a/drivers/gpu/drm/drm_panel.c b/drivers/gpu/drm/drm_panel.c
index 2ef988e037b7..3dfe3c886502 100644
--- a/drivers/gpu/drm/drm_panel.c
+++ b/drivers/gpu/drm/drm_panel.c
@@ -30,12 +30,36 @@
 static DEFINE_MUTEX(panel_lock);
 static LIST_HEAD(panel_list);
 
+/**
+ * DOC: drm panel
+ *
+ * The DRM panel helpers allow drivers to register panel objects with a
+ * central registry and provide functions to retrieve those panels in display
+ * drivers.
+ */
+
+/**
+ * drm_panel_init - initialize a panel
+ * @panel: DRM panel
+ *
+ * Sets up internal fields of the panel so that it can subsequently be added
+ * to the registry.
+ */
 void drm_panel_init(struct drm_panel *panel)
 {
 	INIT_LIST_HEAD(&panel->list);
 }
 EXPORT_SYMBOL(drm_panel_init);
 
+/**
+ * drm_panel_add - add a panel to the global registry
+ * @panel: panel to add
+ *
+ * Add a panel to the global registry so that it can be looked up by display
+ * drivers.
+ *
+ * Return: 0 on success or a negative error code on failure.
+ */
 int drm_panel_add(struct drm_panel *panel)
 {
 	mutex_lock(&panel_lock);
@@ -46,6 +70,12 @@ int drm_panel_add(struct drm_panel *panel)
 }
 EXPORT_SYMBOL(drm_panel_add);
 
+/**
+ * drm_panel_remove - remove a panel from the global registry
+ * @panel: DRM panel
+ *
+ * Removes a panel from the global registry.
+ */
 void drm_panel_remove(struct drm_panel *panel)
 {
 	mutex_lock(&panel_lock);
@@ -54,6 +84,18 @@ void drm_panel_remove(struct drm_panel *panel)
 }
 EXPORT_SYMBOL(drm_panel_remove);
 
+/**
+ * drm_panel_attach - attach a panel to a connector
+ * @panel: DRM panel
+ * @connector: DRM connector
+ *
+ * After obtaining a pointer to a DRM panel a display driver calls this
+ * function to attach a panel to a connector.
+ *
+ * An error is returned if the panel is already attached to another connector.
+ *
+ * Return: 0 on success or a negative error code on failure.
+ */
 int drm_panel_attach(struct drm_panel *panel, struct drm_connector *connector)
 {
 	if (panel->connector)
@@ -66,6 +108,15 @@ int drm_panel_attach(struct drm_panel *panel, struct drm_connector *connector)
 }
 EXPORT_SYMBOL(drm_panel_attach);
 
+/**
+ * drm_panel_detach - detach a panel from a connector
+ * @panel: DRM panel
+ *
+ * Detaches a panel from the connector it is attached to. If a panel is not
+ * attached to any connector this is effectively a no-op.
+ *
+ * Return: 0 on success or a negative error code on failure.
+ */
 int drm_panel_detach(struct drm_panel *panel)
 {
 	panel->connector = NULL;
@@ -76,6 +127,16 @@ int drm_panel_detach(struct drm_panel *panel)
 EXPORT_SYMBOL(drm_panel_detach);
 
 #ifdef CONFIG_OF
+/**
+ * of_drm_find_panel - look up a panel using a device tree node
+ * @np: device tree node of the panel
+ *
+ * Searches the set of registered panels for one that matches the given device
+ * tree node. If a matching panel is found, return a pointer to it.
+ *
+ * Return: A pointer to the panel registered for the specified device tree
+ * node or NULL if no panel matching the device tree node can be found.
+ */
 struct drm_panel *of_drm_find_panel(struct device_node *np)
 {
 	struct drm_panel *panel;
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 73299f9e77a8..a297e1ffafb5 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -12032,11 +12032,16 @@ static void intel_modeset_update_connector_atomic_state(struct drm_device *dev)
 	struct intel_connector *connector;
 
 	for_each_intel_connector(dev, connector) {
+		if (connector->base.state->crtc)
+			drm_connector_unreference(&connector->base);
+
 		if (connector->base.encoder) {
 			connector->base.state->best_encoder =
 				connector->base.encoder;
 			connector->base.state->crtc =
 				connector->base.encoder->crtc;
+
+			drm_connector_reference(&connector->base);
 		} else {
 			connector->base.state->best_encoder = NULL;
 			connector->base.state->crtc = NULL;
diff --git a/include/drm/drm_modeset_helper_vtables.h b/include/drm/drm_modeset_helper_vtables.h
index b61c2d45192e..d4619dc2eecb 100644
--- a/include/drm/drm_modeset_helper_vtables.h
+++ b/include/drm/drm_modeset_helper_vtables.h
@@ -672,7 +672,7 @@ struct drm_connector_helper_funcs {
 	 * fixed panel can also manually add specific modes using
 	 * drm_mode_probed_add(). Drivers which manually add modes should also
 	 * make sure that the @display_info, @width_mm and @height_mm fields of the
-	 * struct #drm_connector are filled in.
+	 * struct &drm_connector are filled in.
 	 *
 	 * Virtual drivers that just want some standard VESA mode with a given
 	 * resolution can call drm_add_modes_noedid(), and mark the preferred
diff --git a/include/drm/drm_panel.h b/include/drm/drm_panel.h
index 13ff44b28893..220d1e2b3db1 100644
--- a/include/drm/drm_panel.h
+++ b/include/drm/drm_panel.h
@@ -75,6 +75,14 @@ struct drm_panel_funcs {
 			   struct display_timing *timings);
 };
 
+/**
+ * struct drm_panel - DRM panel object
+ * @drm: DRM device owning the panel
+ * @connector: DRM connector that the panel is attached to
+ * @dev: parent device of the panel
+ * @funcs: operations that can be performed on the panel
+ * @list: panel entry in registry
+ */
 struct drm_panel {
 	struct drm_device *drm;
 	struct drm_connector *connector;
@@ -85,6 +93,17 @@ struct drm_panel {
 	struct list_head list;
 };
 
+/**
+ * drm_disable_unprepare - power off a panel
+ * @panel: DRM panel
+ *
+ * Calling this function will completely power off a panel (assert the panel's
+ * reset, turn off power supplies, ...). After this function has completed, it
+ * is usually no longer possible to communicate with the panel until another
+ * call to drm_panel_prepare().
+ *
+ * Return: 0 on success or a negative error code on failure.
+ */
 static inline int drm_panel_unprepare(struct drm_panel *panel)
 {
 	if (panel && panel->funcs && panel->funcs->unprepare)
@@ -93,6 +112,16 @@ static inline int drm_panel_unprepare(struct drm_panel *panel)
 	return panel ? -ENOSYS : -EINVAL;
 }
 
+/**
+ * drm_panel_disable - disable a panel
+ * @panel: DRM panel
+ *
+ * This will typically turn off the panel's backlight or disable the display
+ * drivers. For smart panels it should still be possible to communicate with
+ * the integrated circuitry via any command bus after this call.
+ *
+ * Return: 0 on success or a negative error code on failure.
+ */
 static inline int drm_panel_disable(struct drm_panel *panel)
 {
 	if (panel && panel->funcs && panel->funcs->disable)
@@ -101,6 +130,16 @@ static inline int drm_panel_disable(struct drm_panel *panel)
 	return panel ? -ENOSYS : -EINVAL;
 }
 
+/**
+ * drm_panel_prepare - power on a panel
+ * @panel: DRM panel
+ *
+ * Calling this function will enable power and deassert any reset signals to
+ * the panel. After this has completed it is possible to communicate with any
+ * integrated circuitry via a command bus.
+ *
+ * Return: 0 on success or a negative error code on failure.
+ */
 static inline int drm_panel_prepare(struct drm_panel *panel)
 {
 	if (panel && panel->funcs && panel->funcs->prepare)
@@ -109,6 +148,16 @@ static inline int drm_panel_prepare(struct drm_panel *panel)
 	return panel ? -ENOSYS : -EINVAL;
 }
 
+/**
+ * drm_panel_enable - enable a panel
+ * @panel: DRM panel
+ *
+ * Calling this function will cause the panel display drivers to be turned on
+ * and the backlight to be enabled. Content will be visible on screen after
+ * this call completes.
+ *
+ * Return: 0 on success or a negative error code on failure.
+ */
 static inline int drm_panel_enable(struct drm_panel *panel)
 {
 	if (panel && panel->funcs && panel->funcs->enable)
@@ -117,6 +166,16 @@ static inline int drm_panel_enable(struct drm_panel *panel)
 	return panel ? -ENOSYS : -EINVAL;
 }
 
+/**
+ * drm_panel_get_modes - probe the available display modes of a panel
+ * @panel: DRM panel
+ *
+ * The modes probed from the panel are automatically added to the connector
+ * that the panel is attached to.
+ *
+ * Return: The number of modes available from the panel on success or a
+ * negative error code on failure.
+ */
 static inline int drm_panel_get_modes(struct drm_panel *panel)
 {
 	if (panel && panel->funcs && panel->funcs->get_modes)